pith. sign in

arxiv: 2604.11630 · v1 · submitted 2026-04-13 · ❄️ cond-mat.str-el

Quasi-linear `non-metallic' resistivity in the distorted-kagome metal CrPdAs

Benny Lau , Wenlong Wu , Bo Yuan , Julian Nickel , Stephen Julian This is my paper

Pith reviewed 2026-05-10 15:46 UTC · model grok-4.3

classification ❄️ cond-mat.str-el
keywords CrPdAsdistorted kagomenon-metallic resistivityspin-glassDirac bandsanti-site disorderspecific heatkagome metal
0
0 comments X

The pith

CrPdAs shows quasi-linear non-metallic resistivity from 300 K to 2 K with no saturation.

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

The paper grows and characterizes single crystals of the distorted-kagome compound CrPdAs. It finds spin-glass order near 60 K, a large linear specific-heat coefficient, and Dirac band crossings near the Fermi level that split under spin-orbit coupling. The central observation is that the in-plane resistivity remains non-metallic across the entire measured range and becomes quasi-linear below roughly 130 K without any sign of saturation at the lowest temperatures. A reader would care because this transport behavior departs from ordinary metallic expectations in a kagome lattice system that also hosts magnetic order and topological band features.

Core claim

Single-phase crystals of CrPdAs with approximately 29 percent Cr-Pd anti-site disorder display spin-glass behavior at about 60 K and a Sommerfeld coefficient of 23 mJ per mole per K squared. The in-plane resistivity is non-metallic from 300 K down to 2 K, quasi-linear below 130 K, and shows no saturation at the lowest temperatures reached.

What carries the argument

the quasi-linear non-metallic in-plane resistivity observed across the full temperature range in the presence of the distorted kagome lattice and anti-site disorder

If this is right

  • The resistivity remains non-metallic and quasi-linear even after annealing removes the ferromagnetic impurity phase.
  • Dirac crossings near the Fermi energy split by spin-orbit coupling coexist with the unusual transport.
  • The large linear specific-heat coefficient persists in the single-phase crystals with spin-glass order.
  • No saturation of resistivity occurs down to 2 K despite the material being nominally metallic.

Where Pith is reading between the lines

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

  • If the behavior survives in cleaner samples it may indicate a scattering mechanism tied to the kagome geometry or frustration rather than simple impurity effects.
  • Comparable quasi-linear resistivity could be searched for in other disordered kagome metals to test generality.
  • The combination with Dirac bands near E_F suggests possible interplay between topology and the temperature-independent scattering channel.

Load-bearing premise

The 29 percent anti-site disorder between Cr and Pd does not dominate the measured transport, so the resistivity reflects intrinsic behavior of the distorted-kagome lattice.

What would settle it

Growth of CrPdAs samples with substantially lower anti-site disorder followed by resistivity measurements down to 2 K to test whether the quasi-linear non-metallic behavior disappears.

Figures

Figures reproduced from arXiv: 2604.11630 by Benny Lau, Bo Yuan, Julian Nickel, Stephen Julian, Wenlong Wu.

Figure 1
Figure 1. Figure 1: Left: A view, looking down the c-axis, of the crystal structure of CrPdAs, a TT′X compound with the P62m structure. 3 by 3 unit cells are shown. Right: a single unit cell, viewed from the side. The Cr sites (blue balls) occupy the vertices of a distorted kagome lattice (blue triangles). Pd (green) form trimers. As atoms are shown as pink balls. Note that in CrPdAs there is considerable Cr-Pd antisite disor… view at source ↗
Figure 2
Figure 2. Figure 2: (a) Powder x-ray diffraction on growth G3, fitted with Profex [14]. The inset zooms in on the strong peaks between 2θ = 35 and 51 degrees. There is no sign of secondary phases (cf. sample G1, Appendix B). Despite allowing for rather large grain anisotropy, and also Cr/Pd site disorder, the amplitude of some peaks is not well fitted. (b) Powder neutron diffraction spectrum, fitted by varying the level of an… view at source ↗
Figure 3
Figure 3. Figure 3: (a) Heat capacity vs temperature from room temperature to 2 K, measured on a sample from growth G3. The inset focuses on the region below 150 K, and illustrates enhancement of C(T) around 60 K. (b) C/T vs. T 2 from 10 K to 2 K from the same data as (a). 0 50 100 150 200 250 300 T (K) 0 2 4 6 8 M (10 3 B / f.u.) ZFC FC (a) G1 G2 G3 0 50 100 150 200 250 300 T (K) 0 2 4 6 1/M (a.u.) (b) G1 G2 G3 150 200 250 3… view at source ↗
Figure 4
Figure 4. Figure 4: Magnetization of CrPdAs. (a) Magnetization vs. temperature for polycrystalline samples from our three growth runs, G1, G2 and G3. FC refers to field cooling in a field of 100 Oe, while ZFC refers to samples coolied in zero field, prior to application of an external field of 100 Oe. Sample G1 was measured only in the FC condition. The separation of FC and ZFC curves below 60 K is a possible signature of spi… view at source ↗
Figure 5
Figure 5. Figure 5: (a) Spaghetti plot of the calculated band structure of CrPdAs, without spin-orbit coupling, plotted from -2.0 eV to 2.0 eV, relative to EF . The Brillouin zone is shown on the right. (b) The same band structure as in (a), but zooming in on the region within ±0.1 eV of EF . Across the top of the Brillouin zone (surrounding the H point) there are several band crossings very close to EF (circled). (c) Same co… view at source ↗
Figure 6
Figure 6. Figure 6: Resistivity vs. temperature for CrPdAs, for crystals from growth G3. The c-axis resistivity (upper, blue curve) is relatively weakly temperature dependent, and falls (i.e. is ‘metallic’) across the spin-glass transition at 60 K. The ab-plane resistivity (lower, orange curve) is non-metallic across the entire temperature range, and is quasi-linear below about 130 K, with no apparent change in slope through … view at source ↗
Figure 7
Figure 7. Figure 7: Comparison of ρ(T) for crystals from growths G1 and G3. (a) ρab(T), (b) ρc(T). Note the larger y-axis scale in (a), reflecting the stronger T dependence of ρab(T). In each plot the data have been shifted vertically by a few percent so that they agree at low temperature. The ‘G3’ data is the same as in [PITH_FULL_IMAGE:figures/full_fig_p009_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Comparison of powder x-ray diffraction patterns of samples from growths G1 (red dashed line) and G3 (blue solid line). (a) Spectra over the full measured range of 2θ from 10 to 100 degrees. The main peaks match well between the samples, both in position and width. Variations in height may be due to intrinsic or extrinsic (e.g. grain orientation) effects. (b) There is a very weak impurity-phase signature in… view at source ↗
read the original abstract

We report the growth and characterization of single crystals of the disorted-kagome lattice compound CrPdAs. Spin-glass behaviour with $T_{SG} \sim 60\ {\rm K}$ is observed in all crystals tested. Some growths show in addition a magnetic impurity phase with $T_c$ around 200 K, but annealing produces single-phase crystals without the ferromagnetic impurity phase. Single-phase crystals nevertheless have $29\pm 5\%$ anti-site disorder of the Cr and Pd sites, similar to a previous generation of flux-grown polycrystalline samples. We observe a large linear-coefficient of the heat capacity at low temperature, $\gamma = 23 \pm 3$ mJ/mole\,K$^2$, which is typical of kagome metals. The calculated band structure shows several Dirac band-crossings very near $E_F$ whose degeneracy is lifted when spin-orbit interaction is included. Our most curious finding is a `non-metallic' in-plane resistivity, extending over the entire measured temperature range from 300 K down to 2 K. This resistivity is quasi-linear below about 130 K, and shows no sign of saturation down to the lowest temperature measured.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reports the growth and characterization of single crystals of distorted-kagome CrPdAs. All crystals show spin-glass behavior with T_SG ~60 K; annealing eliminates a secondary ferromagnetic phase but leaves 29±5% Cr/Pd anti-site disorder. Heat capacity yields a large Sommerfeld coefficient γ=23±3 mJ/mol K². DFT calculations find Dirac crossings near E_F that are gapped by SOC. The central observation is a non-metallic in-plane resistivity that remains quasi-linear below ~130 K from 300 K to 2 K with no low-T saturation.

Significance. If the quasi-linear, non-saturating resistivity proves intrinsic to the distorted kagome lattice (rather than disorder-driven), the result would be of interest for transport in kagome metals and possible Dirac-fermion scattering. The reported γ is consistent with other kagome systems, and the standard band-structure calculations provide a conventional electronic-structure baseline.

major comments (2)
  1. [crystal characterization and transport sections] The manuscript reports 29±5% Cr/Pd anti-site disorder in the annealed single-phase crystals (crystal characterization section) yet provides no quantitative estimate of the elastic scattering rate or residual resistivity contribution from this disorder. Without such an estimate (e.g., via Matthiessen’s rule, residual resistivity ratio, or comparison to the calculated clean-limit conductivity), the claim that the observed quasi-linear resistivity reflects intrinsic kagome physics rather than impurity scattering cannot be assessed.
  2. [resistivity results and discussion] In the resistivity data presentation and discussion, the absence of saturation down to 2 K is highlighted as the most curious finding, but no comparison is made between the measured resistivity scale and the expected disorder scattering from the quantified 29% anti-site defects, nor is any calculation of the transport lifetime from the DFT bands (with or without SOC) provided.
minor comments (2)
  1. [abstract] The abstract contains the typographical error “disorted-kagome”; this should be corrected to “distorted-kagome”.
  2. [heat capacity section] The heat-capacity coefficient is written as “mJ/mole K²”; standard notation is “mJ mol⁻¹ K⁻²”.

Simulated Author's Rebuttal

2 responses · 1 unresolved

We thank the referee for their careful review and constructive feedback on our manuscript. We address the major comments point by point below. We have made revisions to incorporate estimates of disorder scattering where possible, but note limitations in performing full transport calculations at this stage.

read point-by-point responses

  1. Referee: The manuscript reports 29±5% Cr/Pd anti-site disorder in the annealed single-phase crystals (crystal characterization section) yet provides no quantitative estimate of the elastic scattering rate or residual resistivity contribution from this disorder. Without such an estimate (e.g., via Matthiessen’s rule, residual resistivity ratio, or comparison to the calculated clean-limit conductivity), the claim that the observed quasi-linear resistivity reflects intrinsic kagome physics rather than impurity scattering cannot be assessed.

    Authors: We agree that providing a quantitative estimate of the disorder contribution is important for assessing whether the quasi-linear resistivity is intrinsic. In the revised manuscript, we have added an estimate in the crystal characterization section using Matthiessen's rule. Assuming a typical scattering rate per anti-site defect in intermetallic compounds, we estimate the residual resistivity due to the 29% disorder to be on the order of the measured low-temperature value. We also report the residual resistivity ratio, which is low, consistent with the high disorder level. This supports that while disorder contributes to the overall resistivity scale, the temperature-dependent quasi-linear behavior over a broad range is indicative of intrinsic scattering mechanisms, such as those potentially arising from the gapped Dirac crossings. revision: yes

  2. Referee: In the resistivity data presentation and discussion, the absence of saturation down to 2 K is highlighted as the most curious finding, but no comparison is made between the measured resistivity scale and the expected disorder scattering from the quantified 29% anti-site defects, nor is any calculation of the transport lifetime from the DFT bands (with or without SOC) provided.

    Authors: We acknowledge the need for such comparisons. We have revised the resistivity results and discussion section to include a direct comparison of the measured resistivity values with the estimated disorder scattering contribution from the anti-site defects. Regarding the transport lifetime calculation from the DFT bands, this would require a full Boltzmann transport calculation, which is not included in the current work. We have added a note discussing the expected scattering from the SOC-gapped Dirac points as a possible intrinsic mechanism, but leave detailed lifetime estimates for future investigation. revision: partial

standing simulated objections not resolved
  • Calculation of the transport lifetime from the DFT bands with or without SOC

Circularity Check

0 steps flagged

No circularity: experimental observations and standard calculations stand independently

full rationale

The paper reports direct experimental results from crystal growth, magnetization, specific-heat, and resistivity measurements on CrPdAs, plus routine DFT band-structure calculations showing Dirac crossings near E_F. No derivations, predictions, or first-principles claims are made that reduce by construction to fitted parameters, self-definitions, or self-citation chains. The quasi-linear resistivity is presented as a measured quantity without any redefinition or statistical forcing from inputs. Any self-citations (e.g., to prior polycrystalline samples) are incidental and non-load-bearing for the central observations.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

This is an experimental materials characterization study. No new theoretical axioms, free parameters, or invented entities are introduced; all reported quantities are measured or computed from standard methods.

pith-pipeline@v0.9.0 · 5521 in / 1075 out tokens · 85422 ms · 2026-05-10T15:46:41.220107+00:00 · methodology

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

31 extracted references · 31 canonical work pages

  1. [1]

    Effects of electronegativity and metallic interactions in phosphites and ternary arsenides of metallic-like transition element-3d, element-4d, element-5d , R.\ Fruchart, Ann.\ Chim.\ Fr.\ 7 , 563 (1982)

    work page 1982

  2. [2]

    CrRhAs: a member of a large family of metallic kagome antiferromagnets , Y.N.\ Huang, H.O.\ Jeschke and I.\ Mazin, npj Quantum Materials 8 (2023) 32

    work page 2023

  3. [3]

    Ferromagnetism in the Hubbard model on line graphs and other considerations , A.\ Mielke, J.\ Phys.\ A 24 (1991) L73

    work page 1991

  4. [4]

    Murakami and N.\ Nagaosa, Phys.\ Rev

    Spin anisotropy and quantum Hall effectin the kagome lattice: Chiral spin state based on a ferromagnet , K.\ Ohgushi, S. Murakami and N.\ Nagaosa, Phys.\ Rev. B 62 (2000) R6065

    work page 2000

  5. [5]

    Matter 404 (2009) 3038

    Magnetic properties of strongly frustrated and correlated systems , C.\ Lacroix, Physica B: Cond. Matter 404 (2009) 3038

    work page 2009

  6. [6]

    Wills, J.\ Phys.\ - Cond.\ Mat.\ 23 (2011) 112205

    The giant anomalous Hall effect in the ferromagnet Fe _3 Sn _2 - a frustrated kagome metal , T.\ Kida, L.A.\ Fenner, A.A.\ Dee, I.\ Terasaki, M.\ Hagiwara and A.S. Wills, J.\ Phys.\ - Cond.\ Mat.\ 23 (2011) 112205

    work page 2011

  7. [7]

    Massive Dirac fermions in a ferromagnetic kagome metal , L.\ Ye, M.\ Kang, J.\ Liu, F.\ von Cube, C.R.\ Wicker, T.\ Suzuki, C.\ Jozwiak, A.\ Bostwick, E.\ Rotenberg, D.C.\ Bell, L.\ Fu, R.\ Comin and J.G.\ Checkelsky, Nature 555 (2018) 638

    work page 2018

  8. [8]

    Fang, M.\ Kang, J.\ Kaufman, Y.\ Lee, C.\ John, P.M.\ Neves, S.Y.F

    Hopping frustruation-induced flat band and strange metallicity in a kagome metal , L.\ Ye, S. Fang, M.\ Kang, J.\ Kaufman, Y.\ Lee, C.\ John, P.M.\ Neves, S.Y.F. Zhao, J.\ Denlinger, C. Jozwiak, A.\ Bostwick, E.\ Rotenberg, E.\ Kaxiras, D.C.\ Bell, O.\ Janson, R.\ Comin and J.G.\ Checkelsky, Nature Physics 20 (2024) 610

    work page 2024

  9. [9]

    Julian, Eur.\ Phys.\ J.\ 85 (2009) 17009

    A novel non-Fermi-liquid state in the iron pnictide FeCrAs , W.\ Wu, A.\ McCollam, I.\ Swainson, P.M.C.\ Rourke, D.G.\ Rancourt and S.R. Julian, Eur.\ Phys.\ J.\ 85 (2009) 17009

    work page 2009

  10. [10]

    Pressure-induced strange metal phase in a metallic kagome ferromagnet , B.\ Shen, F.\ Du, F.\ Breitner, V.A.\ Ginga, E.\ Uykur, A.A.\ Tsirlin and P.\ Gegenwart, arXiv:2503.09524

    work page arXiv

  11. [11]

    T.\ Kanomata, T.\ Kawashima, H.\ Utsugi, T.\ Goto, H.\ Hasegawa and T.\ Kaneko, Magnetic properties of the intermetallic compounds MM'X(M=Cr, Mn, M'=Ru,Rh,Pd, and X=P,As) , J.\ Appl.\ Phys.\ 69 (1991) 4639

    work page 1991

  12. [12]

    T.\ Kaneko, T.\ Kanomata, T.\ Kawashima, S.\ Mori, S.\ Miura and Y.\ Nakagawa, High-field magnetization in intermetallic compounds MM'Z (M=Mn, Cr; M' = Ru,Rh, Pd; X = As,P) , Physica B 177 123 (1992)

    work page 1992

  13. [13]

    Influence de l'ectronegativite sure l'apparaition de l'ordere dan les phases mm'p et mm'as des metaux de transition , M.\ Roy-Montreuil, B.\ Deyris, A.\ Michel, R.\ Fruchart, J.P.\ Senateur, D.\ Boursier, Ann.\ Chim.\ 4 (1979) 411

    work page 1979

  14. [14]

    and Kleeberg, R., 2015

    Profex: a graphical user interface for the Rietveld refinement program BGMN , N. D\"obelin and R.\ Kleeberg, J. Appl. Crystallography 48 (2015) 1573-1580. doi:10.1107/S1600576715014685

    work page doi:10.1107/s1600576715014685 2015

  15. [15]

    YCr _6 Ge _6 as a candidate compound for a kagome metal , Y.\ Ishii, H.\ Harima, Y.\ Okamoto, J.-I.\ Yamaura and Z.\ Hiroi, J.\ Phys.\ Soc.\ Jpn.\ 82 (2013) 023705

    work page 2013

  16. [16]

    Rodriguez-Rivera, J.R.\ Nelson, S.D.\ Wilson, E.\ Ertekin, T.M.\ McQueen and E.S.\ Toberer, Phys.\ Rev.\ Materials 3 (2019) 094407

    New kagome prototype materials: discovery of KV _3 Sb _5 , RbV _3 Sb _5 and CsV _3 Sb _5 , B.R.\ Ortiz, L.C.\ Gomes, J.R.\ Morey, M.\ Winiarski, M.\ Bordelon, J.S.\ Mangum, I.W.H.\ Oswald, J.A. Rodriguez-Rivera, J.R.\ Nelson, S.D.\ Wilson, E.\ Ertekin, T.M.\ McQueen and E.S.\ Toberer, Phys.\ Rev.\ Materials 3 (2019) 094407

    work page 2019

  17. [17]

    New kagome metal Sc _3 Mn _3 Al _7 Si _5 and it gallium-doped analogues: synthesis, crystal structure, and physical properties , H.\ He, W.\ Miller and M.C.\ Aronson, Inorg.\ Chem.\ 53 (2014) 9115

    work page 2014

  18. [18]

    Frequency and field dependence of the ac susceptibility of the AuMn spin-glass , C.A.M.\ Mulder, A.J.\ van Duyneveldt and J.A.\ Mydosh, Phys.\ Rev.\ B 25 (1982) 515

    work page 1982

  19. [19]

    Harrison, Science 348 (2015) 317

    Quasiparticle mass enhancement approaching optimal doping in a high-T _c superconductor , B.J.\ Ramshaw, S.E.\ Sebastian, R.D.\ McDonald, J.\ Day, B.S.\ Tan, Z.\ Zhu, J.B.\ Betts, R.\ Liang, D.A.\ Bonn, W.N.\ Hardy and N. Harrison, Science 348 (2015) 317

    work page 2015

  20. [20]

    Stranger than metals , P.W.\ Phillips, N.E.\ Hussey and P.\ Abbamonte, Science 377 (2022) 169

    work page 2022

  21. [21]

    J.\ Zaanen, Why the temperature is so high , Nature 430 (2004) 512

    work page 2004

  22. [22]

    Similarity of scattering rates in metals showing T -linear resistivity , J.A.N.\ Bruin, H.\ Sakai, R.S.\ Perry and A.P Mackenzie, Science 339 (2013) 804

    work page 2013

  23. [23]

    Evidence for non-Fermi-liquid behavior in the Kondo alloy Y _ 1-x U _ x Pd _3 , C.L.\ Seaman, M.B.\ Maple, S.\ Ghamaty, M.S.\ Torikachvili, J.-S.\ Kang, L.Z.\ Liu, J.W.\ Allen and D.L.\ Cox, Phys.\ Rev.\ Lett.\ 67 (1991) 2882

    work page 1991

  24. [24]

    Non Fermi liquid ground states in strongly-correlated f-electron metals , M.B.\ Maple, M.C.\ de Andrade, J.\ Herrmann, Y.\ Dalichaouch, D.A.\ Gajewski, C.L.\ Seaman, R.\ Chau, R.\ Movshovich, M.C.\ Aronson and R.\ Osborn, J.\ Low Temp.\ Phys.\ 99 (1995) 223

    work page 1995

  25. [25]

    E.\ Miranda, V.\ Dobrosavljevi\'c and G

    Disorder-driven non-Fermi-liquid behavior in Kondo alloys . E.\ Miranda, V.\ Dobrosavljevi\'c and G. Kotliar, Phys.\ Rev.\ Lett.\ 78 (1997) 290

    work page 1997

  26. [26]

    Non-Fermi liquid behavior and Griffiths phase in f -electron compounds , A.H.\ Castro Neto, G.\ Castilla and B.A.\ Jones, Phys.\ Rev.\ Lett.\ 81 (1998) 3531

    work page 1998

  27. [27]

    Kondo resonance narrowing in d - and f -electron systems , A.H.\ Nevidomskyy and P.\ Coleman, Phys.\ Rev.\ Lett.\ 103 (2009) 147205

    work page 2009

  28. [28]

    WIEN2k: An APW\_lo program for calculating the properties of solids , P.\ Blaha, K.\ Schwarz, F.\ Tran, R.\ Laskowski, G.K.H.\ Madsen and L.D.\ Marks, J.\ Chem.\ Phys.\ 152 (2020) 074101

    work page 2020

  29. [29]

    Enhanced N\'eel temperature and unusual thermal expansion in flux-grown FeCrAs crystals , M.A.\ McGuire, M.S.\ Cook, B.R.\ Ortiz, J.\ Yan and A.F.\ May, arxiv:2505.21735

    work page arXiv

  30. [30]

    Tuning the flat bands of the kagome metal CoSn with Fe, In or Ni doping , B.C.\ Sales, W.R.\ Meier, A.F.\ May, J.\ Xing, J.-Q.\ Yan and M.A.\ McGuire, Phys.\ Rev.\ Materials 5 (2021) 044202

    work page 2021

  31. [31]

    Revealing an anisotropic electronic scattering rate

    work page