Pith. sign in

REVIEW 3 major objections 6 minor 60 references

A germanium two-hole qubit can idle with both exchange and Zeeman difference off, then use only baseband voltages for independent X and Z rotations at 99.53% gate fidelity.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

A germanium two-hole singlet–triplet qubit is made fully degenerate at idle and driven with all-electrical orthogonal X and Z gates at 99.53% average physical fidelity.

T0 review reviewed 2026-07-30 challenge →

load-bearing objection Real experimental advance: two-hole Ge ST qubit with electrically zeroed idle and baseband orthogonal X/Z, backed by spectroscopy and RB, not just a rebrand of known g-tuning. the 3 major comments →

arxiv 2607.27067 v1 pith:NBSDUHBP submitted 2026-07-29 cond-mat.mes-hall quant-ph

A Degenerate Singlet-Triplet Qubit with All-Electrical Orthogonal Control

classification cond-mat.mes-hall quant-ph PACS 73.21.La03.67.Lx85.35.Be71.70.Ej
keywords singlet-triplet qubitdegenerate idlehole spinsgermanium quantum dotsall-electrical controlorthogonal rotationsg-factor tuningbaseband pulses
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Standard singlet–triplet qubits leave a fixed Zeeman energy difference always on, so the idle point keeps rotating and the two control axes are not independent. This paper shows that the electrically tunable, anisotropic g-factors of holes in a germanium double quantum dot can be set so that both the exchange interaction J and the Zeeman difference ΔEZ vanish at once. From that true degenerate idle, ordinary baseband voltage pulses alone turn J and ΔEZ on and off independently, giving clean Z and X rotations on the Bloch sphere. Randomized benchmarking reports an average physical single-qubit gate fidelity of 99.53% for roughly 100 ns gates, and the same electrical knobs move the degenerate point across magnetic-field angles into a quieter coherence regime. A sympathetic reader cares because the scheme removes always-on idle rotations, needs no micromagnets or RF drives for single-qubit control, and points toward arrays that share one global field while still allowing local electrical tuning.

Core claim

By electrically tuning the anisotropic g-factors of two hole spins in a Ge double quantum dot, both the exchange J and the Zeeman difference ΔEZ can be set simultaneously to zero, creating a degenerate S–T0 idle from which baseband voltage pulses alone implement fully orthogonal X (ΔEZ) and Z (J) rotations, with randomized-benchmarking average physical single-qubit fidelity 99.53(9)% at ~100 ns gate duration.

What carries the argument

The degenerate singlet–triplet (DST) idle point: the voltage-tuned operating regime in which both J = 0 and ΔEZ = 0, so the computational states |S⟩ and |T0⟩ are energetically degenerate and the only Hamiltonian during idle is the identity; virtual gates VΔEZ and VJ then restore each term independently.

Load-bearing premise

That the calibrated voltage combinations that turn J and ΔEZ on and off stay cleanly independent under the pulse sizes and idle times used for gates, without leftover always-on couplings or drift that would reintroduce a finite idle Hamiltonian.

What would settle it

Measure the idle evolution of a prepared equatorial state for many microseconds with both control voltages held at the claimed zero point; any coherent precession or contrast loss beyond the reported T2* would show residual J or ΔEZ and falsify true degeneracy and orthogonality.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • Single-qubit gates need only baseband pulses, removing on-chip RF delivery and heating for this encoding.
  • The idle point can be parked where hyperfine noise is weaker (in-plane low field), lengthening coherence without sacrificing two-axis control.
  • Neighboring DST qubits can be electrically g-matched under one global B while still keeping inter-qubit Zeeman contrast large enough to suppress exchange leakage.
  • No fixed micromagnet gradients are required, simplifying fabrication of larger arrays.
  • Gate quality is already competitive with the best reported singlet–triplet devices while adding true degeneracy.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If g-tensor uniformity improves with materials, the same electrical knobs could still be used deliberately to create controlled inter-qubit Zeeman offsets for leakage-free two-qubit gates.
  • The demonstrated electrical steering of the degenerate point suggests a calibration loop that could keep many DST qubits degenerate under slow global-field drift without per-qubit magnets.
  • Combining the DST idle with existing hole-spin shuttling would give a baseband-only architecture from initialization through multi-qubit operations.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

3 major / 6 minor

Summary. The manuscript reports a degenerate singlet–triplet (DST) qubit encoded in two hole spins in a Ge/SiGe double quantum dot. By electrically tuning the anisotropic g-factors of the two holes, the authors identify a magnetic-field and gate-voltage regime in which both the exchange J and the Zeeman difference ΔEZ vanish, so that |S⟩ and |T0⟩ are degenerate at idle. Baseband virtual-gate pulses then independently activate ΔEZ (X rotations) and J (Z rotations). They demonstrate single-axis Rabi maps, a two-axis sequence confirming axis alignment, coherence times T*2,X = 1.55(1) μs and T*2,Z = 2.32(4) μs, and randomized benchmarking yielding an average physical single-qubit gate fidelity of 99.53(9)% for ~100 ns gates. They further show electrical tuning of the degenerate point over a range of field orientations, with enhanced T*2,X near in-plane B, and discuss multi-qubit leakage suppression via engineered inter-qubit Zeeman detuning.

Significance. If the results hold, this is a clear advance for semiconductor spin qubits. Conventional ST qubits suffer from a fixed, always-on ΔEZ that prevents true orthogonal two-axis control and forces rotating-frame phase tracking. Achieving a voltage-tunable degenerate idle with fully baseband orthogonal X/Z control in a two-dot encoding—without micromagnets or three-spin EO overhead—addresses a long-standing control bottleneck and is directly relevant to scaling under a shared global field. The reported RB fidelity is competitive with state-of-the-art ST work, the g-factor spectroscopy and virtual-gate calibration are concrete and reproducible in principle, and the field-angle tunability of the degenerate point is a useful practical knob. The multi-qubit leakage discussion (Methods G) is theoretical but points to a coherent scaling path. Overall this is a solid experimental contribution appropriate for a high-profile condensed-matter/quantum-device venue.

major comments (3)
  1. [§II.B–C, Eq. 1; Methods E] Central claim of a degenerate idle (Abstract; §II.B–C; Eq. 1): the manuscript asserts that both J and ΔEZ vanish at the operating point, yet the main text does not report a direct free-evolution / Ramsey measurement at nominal idle (VJ = VΔEZ = 0) that bounds any residual coherent splitting ω_idle. Spectroscopy (Fig. 2b–d) and complementary init/readout contrast (Methods E; Extended Data Figs. 2–4) are supportive, and Hahn-echo behavior (Extended Data Fig. 6) is consistent with ΔEZ-dominated noise, but a quantitative upper bound on residual |J| and |ΔEZ| during idling (e.g., from long idle free induction or a calibrated phase-accumulation sequence) is needed to substantiate “degenerate” and “no unwanted state rotations during idling” at the level claimed. Without it, residual ω_idle ≳ few×100 kHz could still accumulate phase over multi-gate sequences even if single-axis Rabi and RB look
  2. [§II.C; Methods E; Extended Data Figs. 2–4] Virtual-gate orthogonality under the amplitudes used for gates and RB (§II.C; Methods E): VΔEZ = (−VB12, VB1) and VJ = (VB12, 0.5·VB1) are calibrated with a compensation ratio quoted as “approximately 0.5” (Extended Data Fig. 4), and the text acknowledges that positive VΔEZ turns on finite J (Extended Data Figs. 2–3). For the claim of “fully orthogonal” X and Z axes at tπ ≈ 100 ns, the paper should state the residual cross-axis angle or residual unwanted Hamiltonian component under the actual pulse amplitudes used in Fig. 3 and in the Clifford set, not only in the spectroscopy/low-amplitude limit. A short quantification (e.g., residual oscillation contrast in the “wrong” init/readout basis at the RB operating point, or fitted axis tilt from the Fig. 3e checkerboard) would close this gap.
  3. [§II.D, Fig. 3f; Methods F] Fidelity interpretation (§II.D, Fig. 3f): Fgate = 99.53(9)% is extracted from Clifford RB with a shared depolarizing parameter and 2.83 physical gates per Clifford (Methods F). The text does not discuss what limits this fidelity (T*2 vs. pulse calibration vs. SPAM vs. residual non-orthogonality) or whether idle intervals between physical gates in the RB sequence were zeroed or phase-tracked. A brief error budget or at least a statement of idle handling during RB is load-bearing for interpreting the number as evidence of a clean degenerate idle rather than of short, high-contrast gates alone.
minor comments (6)
  1. [Fig. 2d; Fig. 3a,c] Fig. 2d inset and positive-VΔEZ regime: the finite-ΔEZ splitting attributed to VB12 when J is off is important for understanding cross-talk; consider marking the VΔEZ = 0 and VJ = 0 loci more explicitly on the Rabi maps in Fig. 3a,c.
  2. [Eq. 1; Fig. 2a] Eq. 1 uses H = −(J/2)σz + (ΔEZ/2)σx. Confirm sign conventions relative to the Bloch-sphere drawing in Fig. 2a and to the pulse polarities in Fig. 3 so that “X” and “Z” labels are unambiguous for readers reconstructing the sequences.
  3. [Abstract; §III; Methods G] Methods G (two-qubit leakage) is useful but purely theoretical; a sentence in the main Discussion clarifying that no two-qubit experiment is reported would avoid over-reading the scaling claim in the Abstract (“route towards multi-qubit scaling”).
  4. [Methods C; Extended Data Fig. 1] Extended Data Fig. 1 and readout calibration: state the typical single-shot assignment fidelity or separation SNR used when converting |S11| to singlet probability, since RB and T*2 fits depend on that calibration.
  5. [§II.C] Typographical/consistency: “adegeneratequbit” spacing in §II.C; ensure ΔEZ vs. ΔEZ and VB12 notation is uniform across main text and Extended Data; arXiv date stamp “July 30, 2026” is fine but check journal submission metadata.
  6. [§II.E; Fig. 4c] Fig. 4c: the claim of no clear gate-fidelity advantage below ~40 mT is important; if RB or quality-factor data exist at 24 mT (Extended Data Fig. 9), a one-line comparison in the main text would strengthen that conclusion.

Circularity Check

0 steps flagged

No significant circularity: experimental measurement paper with independently extracted spectra, Rabi maps, T2*, and RB fidelities.

full rationale

The central claims—degenerate idle (J = ΔEZ = 0), orthogonal baseband X/Z control via virtual gates VΔEZ and VJ, Fgate = 99.53(9)%, and electrical tuning of the g-matched point—are established by direct spectroscopy (Fig. 2b–d), single- and two-axis pulse maps (Fig. 3a–e), exponential fits to Rabi decays, and randomized benchmarking with a shared depolarizing parameter p fitted to measured survival curves (Methods F). Virtual-gate ratios (~0.5 compensation) are calibrated from independent EDSR and contrast maps under complementary init/readout bases (Methods E; Extended Data Figs. 2–4), then validated rather than defined into the fidelity. Citations to prior ST/EO work and g-tensor literature supply context and device methods; none load-bear a uniqueness theorem or force the measured numbers by construction. Multi-qubit leakage formulas in Methods G are prospective theory, not claimed experimental predictions. Standard experimental calibration and fitting do not constitute circular derivation.

Axiom & Free-Parameter Ledger

5 free parameters · 5 axioms · 1 invented entities

Load-bearing content is experimental. Background quantum-dot and ST Hamiltonian physics are standard. Device-specific free parameters are calibration voltages, compensation ratios, and field orientation chosen to null ΔEZ. No new fundamental entities are postulated; 'DST qubit' names an operating regime of the existing ST encoding.

free parameters (5)
  • Magnetic field operating point (|B|, θ) = |B|=40 mT, θ≈0.8° (main); θ scanned, |B| down to 2 mT
    Chosen so the two hole resonance frequencies coincide (θ≈0.8° at |B|=40 mT in the main dataset); retuned per gate-voltage setting in Fig. 4.
  • V_J compensation ratio ΔE_B12_Z / ΔE_B1_Z = ≈0.5
    Empirical ratio ~0.5 used to cancel ΔEZ when pulsing exchange (Extended Data Fig. 4); defines claimed Z-axis purity.
  • Virtual gate definitions V_ΔEZ and V_J = V_ΔEZ=(−1·VB12, 1·VB1); V_J=(1·VB12, 0.5·VB1)
    Linear combinations of VB1 and VB12 chosen for independent X/Z control; amplitudes set for ~100 ns π gates (V_ΔEZ=−40 mV, V_J=−33 mV).
  • Effective Δg under V_ΔEZ pulse = Δg≈0.01
    Inferred from X-gate frequency vs |B| at fixed pulse amplitude (Fig. 4c green dashed fit).
  • RB fit parameters A, B, p = p=0.973(5) → F_gate=99.53(9)%, F_C=98.7(3)%
    Joint depolarizing fit to singlet and triplet RB curves yields reported fidelities.
axioms (5)
  • domain assumption ST qubit Hamiltonian in {|S⟩,|T0⟩} is H = −(J/2)σ_z + (ΔEZ/2)σ_x
    Eq. 1; standard effective two-level model neglecting leakage to T± when |Ē_Z| is large enough.
  • domain assumption Hole g-tensors in Ge/SiGe are anisotropic and electrically tunable via confinement and strain (light-hole/heavy-hole mixing)
    Used throughout Sec. II.B and II.E; grounded in cited Ge hole literature.
  • domain assumption Pauli spin blockade plus RF reflectometry maps S vs T0 to distinguishable charge signals with calibrated probabilities
    Methods C and Extended Data Fig. 1; standard ST readout assumption.
  • domain assumption Clifford RB with the stated gate set and 2.83 physical gates per Clifford correctly estimates average gate fidelity
    Methods F; assumes SPAM absorbed in A,B and gate-independent depolarizing noise to first order.
  • domain assumption Leakage during inter-qubit exchange scales as P_leak ~ (J/ΔE_ST12_Z)^2 and can be sync-nulled at discrete J values
    Methods G Eqs. 2–5; theoretical scaling argument for multi-qubit outlook, not measured here.
invented entities (1)
  • Degenerate singlet–triplet (DST) qubit independent evidence
    purpose: Name the ST operating regime where J=ΔEZ=0 at idle and both axes are electrically restored on demand.
    Not a new physical particle or interaction; a named control regime of the existing two-spin ST encoding. Independent evidence is the spectroscopy null and idle behavior shown in-device.

reviewed 2026-07-30 · how reviews work

0 comments
Cite this review

Pith. "Pith review of A Degenerate Singlet-Triplet Qubit with All-Electrical Orthogonal Control." pith.science (2026). https://pith.science/paper/NBSDUHBP

@misc{pith2026260727067,
  author       = {Pith},
  title        = {Pith review of: A Degenerate Singlet-Triplet Qubit with All-Electrical Orthogonal Control},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/NBSDUHBP}},
  note         = {Machine review of arXiv:2607.27067}
}
Share X Bluesky LinkedIn Reddit HN
read the original abstract

Singlet-triplet qubits offer an attractive encoding for semiconductor quantum computing, combining ancilla-free readout, reduced sensitivity to common-mode noise, and baseband voltage control. However, the Zeeman energy difference $\Delta E_\mathrm{Z}$ is typically fixed by local magnetic field gradients or $g$-factor inhomogeneities, leaving the exchange interaction $J$ as the only dynamically tunable parameter. This always-on $\Delta E_\mathrm{Z}$ precludes orthogonal control of the qubit's rotation axes and introduces unwanted state rotations during idling. Here we demonstrate all-electrical orthogonal control of a degenerate singlet-triplet (DST) qubit formed by two hole spins in a germanium double quantum dot. Exploiting the electrically tunable anisotropic $g$-factors of the two spins, we identify a regime where both $\Delta E_\mathrm{Z}$ and $J$ vanish, making the $S$ and $T_0$ states degenerate at the idle point. By applying only baseband voltage pulses, we independently control both $J$ and $\Delta E_\mathrm{Z}$, enabling fully orthogonal $Z$- and $X$-axis rotations. Randomized benchmarking yields an average physical single-qubit gate fidelity of 99.53\% for a gate duration of approximately 100 ns. Finally, we electrically tune the degenerate point across a wide range of magnetic field orientations, enabling operation in a regime of enhanced coherence time and offering a route towards multi-qubit scaling under a shared global magnetic field.

Figures

Figures reproduced from arXiv: 2607.27067 by Amir Yacoby, Giordano Scappucci, Jann H. Ungerer, Julian Santen, Konstantinos Tsoukalas, Lucas Stehouwer, Menno Veldhorst, Phuong X. Nguyen, Stefan D. Oosterhout, Stefano Bosco, Valentin John.

Figure 1
Figure 1. Figure 1: A two-hole spin device. a, False-colored scanning-electron microscopy image of a nominally identical device design reported in Ref. [30]. The quantum dots are formed under P1 and P2, while a sensing dot is formed under PCS, with one ohmic contact connected to an RF tank circuit, where reflected |S11| signal is measured for readout. b, Charge stability diagram measured by recording |S11| as the virtual plun… view at source ↗
Figure 2
Figure 2. Figure 2: Control over singlet–triplet qubit parameters. a, Bloch-sphere representation of the singlet–triplet qubit. The exchange interaction J and Zeeman-energy difference ∆EZ generate rotations about the Z- and X-axis, respectively. b, RF spectroscopy of the spin-resonance frequencies of the two hole spins as a function of out-of-plane magnetic field angle at fixed amplitude |B| = 40 mT, revealing the degenerate … view at source ↗
Figure 3
Figure 3. Figure 3: Orthogonal two-axis control of the DST qubit. a, Coherent X rotations generated by pulsing the virtual gate V∆EZ , which consists of equal and opposite voltage pulses applied to the virtual gates VB1 and VB12, as illustrated in the pulse sequence shown above. b, X gate oscillations measured at V∆EZ = −40 mV (white dashed line in a). An exponential fit (red solid line) yields a coherence time of T ∗ 2,X = 1… view at source ↗
Figure 4
Figure 4. Figure 4: Magnetic-field dependence of the DST coherence. a, Extracted spin-resonance frequencies of the two holes as a function of magnetic field angle for different values of VB2 (top) and VB1 (middle). The degenerate points, where the two spin frequencies coincide, are indicated by square and triangular markers, respectively. The resulting dependence of the degenerate point on gate voltage is summarized in the bo… view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

60 extracted references · 3 linked inside Pith

  1. [1]

    All gate variables in all figures are virtual gates; the v-prefix is omitted for simplicity unless noted otherwise. E. Initialization, readout and gate orthogonality The spin state of the DST qubit can be initialized in either the S–T0 basis or the↑↓/↓↑ basis, using different ramp speeds and initialization sequences. In both cases, we start in the charge(...

  2. [2]

    3e), we can confirm orthogonal operations at a de- sirable speed (tπ ≈ 100ns): V∆EZ = (−1 ·V B12, 1 ·V B1) andV J = (1·V B12,0.5·V B1)shown in Fig

    and the arbitrary rotation checkerboard-style map (Fig. 3e), we can confirm orthogonal operations at a de- sirable speed (tπ ≈ 100ns): V∆EZ = (−1 ·V B12, 1 ·V B1) andV J = (1·V B12,0.5·V B1)shown in Fig. 3. F. Randomized Benchmarking We construct the 24 Clifford gates using a combina- tion of I, Xπ, Xπ/2, Zπ, and Zπ/2 gates, as shown in Supplementary Tabl...

  3. [3]

    Undseth, O

    B. Undseth, O. Pietx-Casas, E. Raymenants, M. Mehman- doost, M. T. Mądzik, S. G. J. Philips, S. L. de Snoo, D. J. Michalak, S. V. Amitonov, L. Tryputen, B. P. Wuetz, V. Fezzi, D. D. Esposti, A. Sammak, G. Scappucci, and L. M. K. Vandersypen, Physical Review X13, 041015 (2023)

  4. [4]

    Undseth, X

    B. Undseth, X. Xue, M. Mehmandoost, M. Rimbach-Russ, P. T. Eendebak, N. Samkharadze, A. Sammak, V. V. Dobrovitski, G. Scappucci, and L. M. K. Vandersypen, Physical Review Applied19, 044078 (2023)

  5. [5]

    X. Xue, B. Patra, J. P. G. van Dijk, N. Samkharadze, S. Subramanian, A. Corna, B. Paquelet Wuetz, C. Jeon, F. Sheikh, E. Juarez-Hernandez, B. P. Esparza, H. Ram- purawala, B. Carlton, S. Ravikumar, C. Nieva, S. Kim, H.-J. Lee, A. Sammak, G. Scappucci, M. Veldhorst, F. Se- bastiano, M. Babaie, S. Pellerano, E. Charbon, and L. M. K. Vandersypen, Nature593, ...

  6. [6]

    S. K. Bartee, W. Gilbert, K. Zuo, K. Das, T. Tanttu, C. H. Yang, N. Dumoulin Stuyck, S. J. Pauka, R. Y. Su, W. H. Lim, S. Serrano, C. C. Escott, F. E. Hudson, K. M. Itoh, A. Laucht, A. S. Dzurak, and D. J. Reilly, Nature 643, 382 (2025)

  7. [7]

    Loss and D

    D. Loss and D. P. DiVincenzo, Physical Review A57, 120 (1998)

  8. [8]

    C.-A. Wang, V. John, H. Tidjani, C. X. Yu, A. S. Ivlev, C. Déprez, F. van Riggelen-Doelman, B. D. Woods, N. W. Hendrickx, W. I. L. Lawrie, L. E. A. Stehouwer, S. D. Oosterhout, A. Sammak, M. Friesen, G. Scappucci, S. L. de Snoo, M. Rimbach-Russ, F. Borsoi, and M. Veldhorst, Science385, 447 (2024)

  9. [9]

    Levy, Physical Review Letters89, 147902 (2002)

    J. Levy, Physical Review Letters89, 147902 (2002)

  10. [10]

    J. R. Petta, A. C. Johnson, J. M. Taylor, E. A. Laird, A. Yacoby, M. D. Lukin, C. M. Marcus, M. P. Hanson, and A. C. Gossard, Science309, 2180 (2005)

  11. [11]

    D. P. DiVincenzo, D. Bacon, J. Kempe, G. Burkard, and K. B. Whaley, Nature408, 339 (2000)

  12. [12]

    Medford, J

    J. Medford, J. Beil, J. M. Taylor, S. D. Bartlett, A. C. Doherty, E. I. Rashba, D. P. DiVincenzo, H. Lu, A. C. Gossard, and C. M. Marcus, Nature Nanotechnology8, 654 (2013)

  13. [13]

    Bosco and M

    S. Bosco and M. Rimbach-Russ, Physical Review Applied 25, L021002 (2026)

  14. [14]

    Zhang, E

    X. Zhang, E. Morozova, M. Rimbach-Russ, D. Jirovec, T.- K. Hsiao, P. Cova Fariña, C.-A. Wang, S. D. Oosterhout, A. Sammak, G. Scappucci, M. Veldhorst, and L. M. K. Vandersypen, Nature Nanotechnology20, 209 (2025)

  15. [15]

    A. J. Weinstein, M. D. Reed, A. M. Jones, R. W. Andrews, D. Barnes, J. Z. Blumoff, L. E. Euliss, K. Eng, B. H. Fong, S. D. Ha, D. R. Hulbert, C. A. C. Jackson, M. Jura, T. E. Keating, J.Kerckhoff, A.A.Kiselev, J.Matten, G.Sabbir, A. Smith, J. Wright, M. T. Rakher, T. D. Ladd, and M. G. Borselli, Nature615, 817 (2023)

  16. [16]

    Rimbach-Russ, V

    M. Rimbach-Russ, V. John, B. van Straaten, and S. Bosco, Physical Review Letters135, 197001 (2025)

  17. [17]

    Abraham, E

    M. Abraham, E. Acuna, T. S. Adams, M. Akmal, M. R. Alfaro, I. Alvarado, J. Amontree, C. Andrews, R. W. Andrews, M. Antcliffe,et al., arXiv preprint (2026), preprint, 2604.16216

  18. [18]

    M. T. Mądzik, F. Luthi, G. G. Guerreschi, F. A. Mo- hiyaddin, F. Borjans, J. D. Chadwick, M. J. Curry, J. Ziegler, S. Atanasov, P. L. Bavdaz, E. J. Connors, J.Corrigan, H.E.Ercan, R.Flory, H.C.George, B.Harpt, E. Henry, M. M. Islam, N. Khammassi, D. Keith, L. F. Lampert, T. M. Mladenov, R. W. Morris, A. Nethwe- wala, S. Neyens, R. Otten, L. P. Osuna Ibarr...

  19. [19]

    Tomić, P

    P. Tomić, P. Bütler, Y. Wu, B. Raes, C. Godfrin, S. Ku- bicek, J. Jussot, Y. Canvel, Y. Hermans, Y. Shimura, R. Loo, S. Beyne, G. Jaliel, T. Van Caekenberghe, V. Lev- ajac, D. Wan, K. De Greve, W. W. Huang, K. Ensslin, and T. Ihn, arXiv preprint (2025), preprint, 2512.20758

  20. [20]

    Jirovec, A

    D. Jirovec, A. Hofmann, A. Ballabio, P. M. Mutter, G. Ta- vani, M. Botifoll, A. Crippa, J. Kukucka, O. Sagi, F. Mar- tins, J. Saez-Mollejo, I. Prieto, M. Borovkov, J. Arbiol, D. Chrastina, G. Isella, and G. Katsaros, Nature Mate- rials20, 1106 (2021)

  21. [21]

    Liles, D

    S. Liles, D. Halverson, Z. Wang, A. Shamim, R. Eggli, I. K. Jin, J. Hillier, K. Kumar, I. Vorreiter, M. Rendell, et al., Nature Communications15, 7690 (2024)

  22. [22]

    Foletti, H

    S. Foletti, H. Bluhm, D. Mahalu, V. Umansky, and A. Yacoby, Nature Physics5, 903 (2009)

  23. [23]

    X. Wu, D. R. Ward, J. R. Prance, D. Kim, J. K. Gam- ble, R. T. Mohr, Z. Shi, D. E. Savage, M. G. Lagally, M. Friesen, S. N. Coppersmith, and M. A. Eriksson, Proceedings of the National Academy of Sciences111, 11938 (2014)

  24. [24]

    Berritta, T

    F. Berritta, T. Rasmussen, J. A. Krzywda, J. van der Heijden, F. Fedele, S. Fallahi, G. C. Gardner, M. J. Manfra, E. van Nieuwenburg, J. Danon, A. Chatterjee, and F. Kuemmeth, Nature Communications15, 1676 (2024)

  25. [25]

    Martinez, J

    B. Martinez, J. C. Abadillo-Uriel, E. A. Rodríguez-Mena, and Y.-M. Niquet, Physical Review B106, 235426 (2022)

  26. [26]

    N. W. Hendrickx, L. Massai, M. Mergenthaler, F. J. Schupp, S. Paredes, S. W. Bedell, G. Salis, and A. Fuhrer, Nature Materials23, 920 (2024)

  27. [27]

    D. V. Bulaev and D. Loss, Physical Review Letters98, 097202 (2007)

  28. [28]

    Scappucci, C

    G. Scappucci, C. Kloeffel, F. A. Zwanenburg, D. Loss, M. Myronov, J.-J. Zhang, S. De Franceschi, G. Kat- saros, and M. Veldhorst, Nature Reviews Materials6, 926 (2021)

  29. [29]

    N. W. Hendrickx, W. I. L. Lawrie, M. Russ, F. van Riggelen, S. L. de Snoo, R. N. Schouten, A. Sammak, G. Scappucci, and M. Veldhorst, Nature591, 580 (2021)

  30. [30]

    J. J. Dijkema, X. Zhang, A. Bardakas, D. Bouman, A. Cuzzocrea, D. van Driel, D. Girardi, L. E. A. Ste- houwer, G. Scappucci, A.-M. J. Zwerver, and N. W. Hendrickx, arXiv preprint (2026), preprint, 2604.01063

  31. [31]

    Hansen, A

    I. Hansen, A. E. Seedhouse, S. Serrano, A. Nickl, M. Feng, J. Y. Huang, T. Tanttu, N. Dumoulin Stuyck, W. H. Lim, F. E. Hudson, K. M. Itoh, A. Saraiva, A. Laucht, A. S. Dzurak, and C. H. Yang, Nature Communications15, 7656 (2024)

  32. [32]

    V. John, C. X. Yu, B. van Straaten, E. A. Rodríguez- Mena, M. Rodríguez, S. D. Oosterhout, L. E. A. Ste- houwer, G. Scappucci, M. Rimbach-Russ, S. Bosco, F. Borsoi, Y.-M. Niquet, and M. Veldhorst, Nature Com- munications16, 10560 (2025). 11

  33. [33]

    E. G. Kelly, L. Massai, B. Hetényi, M. Pita-Vidal, A. Orekhov, C. Carlsson, I. Seidler, K. Tsoukalas, L. Som- mer, M. Aldeghi, S. W. Bedell, S. Paredes, F. J. Schupp, M. Mergenthaler, A. Fuhrer, G. Salis, and P. Harvey- Collard, arXiv preprint (2025), preprint, 2504.06898

  34. [34]

    Harvey-Collard, B

    P. Harvey-Collard, B. D’Anjou, M. Rudolph, N. T. Ja- cobson, J. Dominguez, G. A. Ten Eyck, J. R. Wendt, T. Pluym, M. P. Lilly, W. A. Coish, M. Pioro-Ladrière, and M. S. Carroll, Physical Review X8, 021046 (2018)

  35. [35]

    M. D. Reed, B. M. Maune, R. W. Andrews, M. G. Borselli, K. Eng, M. P. Jura, A. A. Kiselev, T. D. Ladd, S. T. Merkel, I. Milosavljevic, E. J. Pritchett, M. T. Rakher, R. S. Ross, A. E. Schmitz, A. Smith, J. A. Wright, M. F. Gyure, and A. T. Hunter, Physical Review Letters116, 110402 (2016)

  36. [36]

    Jirovec, P

    D. Jirovec, P. M. Mutter, A. Hofmann, A. Crippa, M. Rychetsky, D. L. Craig, J. Kukucka, F. Martins, A. Ballabio, N. Ares,et al., Physical review letters128, 126803 (2022)

  37. [37]

    Tsoukalas, U

    K. Tsoukalas, U. von Lüpke, A. Orekhov, B. Hetényi, I. Seidler, L. Sommer, E. G. Kelly, L. Massai, M. Aldeghi, M. Pita-Vidal, N. W. Hendrickx, S. W. Bedell, S. Pare- des, F. J. Schupp, M. Mergenthaler, G. Salis, A. Fuhrer, and P. Harvey-Collard, Nature Communications17, 699 (2026)

  38. [38]

    Veldhorst, Nature577, 487 (2020)

    N.W.Hendrickx, D.P.Franke, A.Sammak, G.Scappucci, and M. Veldhorst, Nature577, 487 (2020)

  39. [39]

    M. J. Carballido, S. Svab, R. S. Eggli, T. Patlatiuk, P. Chevalier Kwon, J. Schuff, R. M. Kaiser, L. C. Camen- zind, A. Li, N. Ares,et al., Nature Communications16, 7616 (2025)

  40. [40]

    Bassi, E

    M. Bassi, E. Rodríguez-Mena, B. Brun, S. Zihlmann, T. Nguyen, V. Champain, J. C. Abadillo-Uriel, B. Bertrand, H. Niebojewski, R. Maurand,et al., Na- ture Physics22, 75 (2026)

  41. [41]

    Cova Fariña, D

    P. Cova Fariña, D. Jirovec, X. Zhang, E. Morozova, S. D. Oosterhout, S. Reale, T.-K. Hsiao, G. Scappucci, M. Veld- horst, and L. M. K. Vandersypen, arXiv preprint (2025), preprint, 2506.08663

  42. [42]

    Takeda, A

    K. Takeda, A. Noiri, J. Yoneda, T. Nakajima, and S. Tarucha, Physical Review Letters124, 117701 (2020)

  43. [43]

    Cerfontaine, T

    P. Cerfontaine, T. Botzem, J. Ritzmann, S. S. Humpohl, A. Ludwig, D. Schuh, D. Bougeard, A. D. Wieck, and H. Bluhm, Nature Communications11, 4144 (2020)

  44. [44]

    Sommer, I

    L. Sommer, I. Seidler, F. J. Schupp, S. Paredes, N. W. Hendrickx, L. Massai, K. Tsoukalas, A. Orekhov, E. G. Kelly, S. W. Bedell, G. Salis, M. Mergenthaler, P. Harvey- Collard, A. Fuhrer, and T. Ihn, Nano Letters26, 8117 (2026)

  45. [45]

    Bosco, M

    S. Bosco, M. Benito, C. Adelsberger, and D. Loss, Phys- ical Review B104, 115425 (2021)

  46. [46]

    S. D. Liles, F. Martins, D. Miserev, A. A. Kiselev, I. Thor- valdson, M. J. Rendell, I. Jin, F. E. Hudson, M. Veldhorst, K. M. Itoh,et al., Physical Review B104, 235303 (2021)

  47. [47]

    J. C. Abadillo-Uriel, E. A. Rodríguez-Mena, B. Martinez, and Y.-M. Niquet, Physical Review Letters131, 097002 (2023)

  48. [48]

    I.Seidler, B.Hetényi, L.Sommer, L.Massai, K.Tsoukalas, E. G. Kelly, A. Orekhov, M. Aldeghi, S. W. Bedell, S. Paredes, F. J. Schupp, M. Mergenthaler, G. Salis, A. Fuhrer, and P. Harvey-Collard, arXiv preprint (2025), preprint, 2510.03125

  49. [49]

    Bosco and D

    S. Bosco and D. Loss, Physical Review Letters127, 190501 (2021)

  50. [50]

    Lodari, O

    M. Lodari, O. Kong, M. Rendell, A. Tosato, A. Sammak, M. Veldhorst, A. R. Hamilton, and G. Scappucci, Applied Physics Letters120, 122104 (2022)

  51. [51]

    Massai, B

    L. Massai, B. Hetényi, M. Mergenthaler, F. J. Schupp, L. Sommer, S. Paredes, S. W. Bedell, P. Harvey-Collard, G. Salis, A. Fuhrer, and N. W. Hendrickx, Communica- tions Materials5, 151 (2024)

  52. [52]

    L. E. A. Stehouwer, C. X. Yu, B. van Straaten, A. Tosato, V. John, D. Degli Esposti, A. Elsayed, D. Costa, S. D. Oosterhout, N. W. Hendrickx, M. Veldhorst, F. Borsoi, and G. Scappucci, Nature Materials24, 1906 (2025)

  53. [53]

    K. Itoh, W. L. Hansen, E. E. Haller, J. W. Farmer, V. I. Ozhogin, A. Rudnev, and A. Tikhomirov, Journal of Materials Research8, 1341 (1993)

  54. [54]

    Spethmann, S

    M. Spethmann, S. Bosco, A. Hofmann, J. Klinovaja, and D. Loss, Physical Review B109, 085303 (2024)

  55. [55]

    Ni, R.-L

    M. Ni, R.-L. Ma, Z.-Z. Kong, N. Chu, S.-K. Zhu, C. Wang, A.-R. Li, W.-Z. Liao, G. Cao, G.-L. Wang, G.-C. Guo, X. Hu, H.-O. Li, and G.-P. Guo, Physical Review Applied 23, 024065 (2025)

  56. [56]

    Corley-Wiciak, C

    C. Corley-Wiciak, C. Richter, M. H. Zoellner, I. Zaitsev, C. L. Manganelli, E. Zatterin, T. U. Schülli, A. A. Corley- Wiciak, J. Katzer, F. Reichmann, W. M. Klesse, N. W. Hendrickx, A. Sammak, M. Veldhorst, G. Scappucci, M. Virgilio, and G. Capellini, ACS Applied Materials & Interfaces15, 3119 (2023)

  57. [57]

    Valvo, M

    E. Valvo, M. Jakob, P. Del Vecchio, M. Rimbach-Russ, and S. Bosco, arXiv preprint (2025), preprint, 2512.12702

  58. [58]

    Tidjani, A

    H. Tidjani, A. Tosato, A. Ivlev, C. Déprez, S. Oosterhout, L. Stehouwer, A. Sammak, G. Scappucci, and M. Veld- horst, Physical Review Applied20, 054035 (2023)

  59. [59]

    Tidjani, D

    H. Tidjani, D. Denora, M. Chan, J. H. Ungerer, B. van Straaten, S. D. Oosterhout, L. Stehouwer, G. Scap- pucci, and M. Veldhorst, arXiv preprint (2025), preprint, 2512.01634

  60. [60]

    Sammak, D

    A. Sammak, D. Sabbagh, N. W. Hendrickx, M. Lodari, B. Paquelet Wuetz, A. Tosato, L. Yeoh, M. Bollani, M. Virgilio, M. A. Schubert, P. Zaumseil, G. Capellini, M. Veldhorst, and G. Scappucci, Advanced Functional Materials29, 1807613 (2019)

This paper was first reviewed by grok-4.5 on July 30, 2026.