Imaging of van der Waals Materials via Standing-Wave Photoemission Microscopy: Depth-Resolved Electronic Structure of WS2

A. Bansil; A. Fadul; A. Tiwari; A. X. Gray; B. T. Jonker; C. M. Schneider; E. Gullikson; F. Kronast; F. Salmassi; J. Katoch

REVIEW 3 major objections 3 minor 10 references

Imaging of van der Waals Materials via Standing-Wave Photoemission Microscopy: Depth-Resolved Electronic Structure of WS2

T0 review · 3 major / 3 minor · reviewed 2026-08-01 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗ Review JSON

Pith's one-line read Standing-wave photoemission microscopy resolves the electronic states of the top and bottom sulfur planes in a single WS2 monolayer and attributes a ~0.2 eV valence-band shift to sulfur surface species.

desk verdict Solid SW-PEEM depth-selectivity demonstration on monolayer WS2, but the ~0.2 eV 'shift' and its S8 attribution are weaker than the prose suggests — likely a superposition artifact. read the letter →

arxiv 2607.23073 v1 pith:PVYQQTO4 submitted 2026-07-25 cond-mat.mtrl-sci

J. R. Paudel , R. Muzzio , M. E. Matzelle , S. Sheikh , A. Fadul , A. Tiwari , F. Salmassi , E. Gullikson

show 8 more authors

K. M. McCreary B. T. Jonker J. Nieminen C. M. Schneider F. Kronast A. Bansil J. Katoch A. X. Gray

This is my paper · ORCID

classification cond-mat.mtrl-sci

keywords standing-wavephotoemissionmicroscopyWS2monolayerdepth-resolvedelectronicstructurevanderWaalsmaterialsX-raystandingwavessulfursurfacespeciesvalence-bandshiftelectron

verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

The paper claims that standing-wave photoemission electron microscopy (SW-PEEM) can resolve electronic structure with Ångstrom depth selectivity inside a single monolayer of WS2, distinguishing the top and bottom sulfur atomic planes. Tuning the X-ray standing wave to 680 eV versus 630 eV selectively enhances the top versus bottom sulfur layers, and the valence-band spectra obtained this way differ by a ~0.2 eV shift in sulfur-derived spectral weight. The authors argue that this shift is not caused by hybridization with the W/C multilayer substrate, whose van der Waals gap is 5 Å, but by sulfur-related surface species such as S8, supported by density functional theory calculations. If correct, SW-PEEM becomes a non-destructive depth-resolved probe for 2D materials, capturing interfacial coupling and chemical reconstruction that are invisible to ordinary surface probes.

What carries the argument

The central mechanism is the soft X-ray standing wave created by Bragg reflection from the W/C multilayer mirror: tuning the photon energy translates the E2 antinodes vertically with sub-nanometre precision. The YXRO optical model is fitted simultaneously to W 4f, S 2p, and C 1s photoemission yield curves to determine the vertical structure (vdW gap 5 Å, S-plane photoemitting width 1.41 Å), and the resulting field profiles identify 630 eV as bottom-sulfur-enhanced and 680 eV as top-sulfur-enhanced. DFT calculations (graphene/WS2 for substrate coupling and S8/WS2 for surface species) then distinguish the two candidate mechanisms for the 0.2 eV shift.

What would settle it

Measure SW-PEEM on a monolayer WS2 that has been cleaned in ultrahigh vacuum (e.g., by gentle annealing) so that elemental-sulfur surface species are absent; if the ~0.2 eV shift between the 630 eV and 680 eV valence-band spectra persists, the paper's central attribution to sulfur surface species is wrong. Independently, cross-sectional STEM of the same flake could verify the fitted 5 Å vdW gap and 1.41 Å S-plane widths, checking whether the structural model underlying the depth labeling is physical.

Watch

Extended reading notes

Core claim

The core discovery is that by scanning the photon energy around the first-order Bragg condition of a W/C multilayer substrate, the standing-wave antinode can be moved through the 3.97 Å-thick WS2 monolayer so that photoemission is dominated by either the bottom sulfur layer (at ~630 eV) or the top sulfur layer (at ~680 eV). The sulfur-derived valence-band spectra recorded in these two geometries differ by ~0.2 eV, with the top-sulfur spectrum shifted toward the Fermi level. Through X-ray optical modeling and DFT calculations, the authors trace this shift to elemental-sulfur-like surface species (modeled by S8) rather than to direct substrate hybridization, establishing SW-PEEM as an Å-scale

Load-bearing premise

The claim that the 630 eV and 680 eV spectra come from the bottom and top sulfur planes rests entirely on a structural fit (vdW gap 5 Å, WS2 thickness 3.97 Å, S-plane width 1.41 Å, C capping 47.4 Å) that is reported without uncertainties; if that fit is non-unique or the actual field distribution differs due to flake waviness or the strained substrate, the top/bottom sulfur labeling—and with it the 0.2 eV shift interpretation—collapses.

Editorial extensions

If this is right

SW-PEEM can non-destructively provide Å-scale depth-resolved chemical and valence-band maps of 2D materials, including within a single monolayer.
Depth-selective valence-band spectroscopy is possible for top versus bottom chalcogen atom planes, enabling direct observation of layer-dependent electronic structure.
The ~0.2 eV shift between top and bottom sulfur spectral weight is attributed to sulfur-related surface species rather than strong substrate hybridization.
The fitted structural model yields a vdW gap of 5 Å and a WS2 monolayer thickness of 3.97 Å, consistent with the AFM step height of ~8 Å.
The technique is positioned to probe interfacial coupling, chemical reconstruction, and emergent states in van der Waals heterostructures and moiré systems.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

If the depth labeling holds, the same approach could resolve layer-resolved electronic structure in bilayer and twisted heterostructures, where the interlayer twist angle governs depth-dependent hybridization.
The observed shift suggests that even gentle polymer-stamp transfer leaves sulfur species on the top surface; this could be a general source of inconsistency between exfoliated and as-grown 2D semiconductor measurements.
The fitted difference between S 2p (1.41 Å) and W 4f (1.15 Å) photoemitting widths hints that standing-wave techniques could offer orbital-selective depth profiling, not just layer counting.
A direct test of the S8 hypothesis would be to measure the same sample before and after mild annealing in vacuum, which should remove or alter surface sulfur species and reduce the 0.2 eV shift.

Share X Bluesky LinkedIn Reddit HN

Signed reviews

No signed human review yet.

Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

read the letter

The headline is that this is a credible technique demonstration with an overreaching physical attribution. The authors show that standing-wave photoemission can distinguish top from bottom sulfur planes in a monolayer WS2, and they back it with a simultaneous YXRO fit to four yield curves, an AFM cross-check, and a clean internal test: the C 2sp valence feature lights up at 630 eV where the model puts the antinode in the carbon cap. That part is convincing and genuinely new for 2D TMDs.

The soft spot is the ~0.2 eV "shift" and the S8 story. The shift is presented without error bars, repeat measurements, or binding-energy calibration details, so its significance is hard to assess. More importantly, the DFT support does not do what the text claims. The SI explicitly places S8 7.5 Å above the WS2 to eliminate bonding interactions, making the combined DOS a simple sum of non-interacting parts. Under that condition, adding S8 spectral weight near the Fermi level shifts the centroid of the S-derived feature by construction; it does not shift the WS2 electronic structure. The 680 eV spectrum also shows extra S2p weight at ~163.5 eV, so the observed valence-band change can be fully explained by an S8 component riding on the WS2 spectrum, with no real shift of WS2 states. The paper's language of "relative binding-energy shift" and "shift toward the Fermi level" overstates what this calculation supports. This is a load-bearing flaw in the attribution, not a minor complaint.

The structural-model uncertainty is real but less damaging. The fit is self-consistent and cross-checked, though the fitted parameters carry no error bars, and the depth assignments depend on the field profile. If the fit is non-unique, the top/bottom labeling loosens, but the internal consistency checks give me reasonable confidence in the depth selectivity itself.

Bottom line: the depth-resolved spectromicroscopy demonstration deserves refereeing and will likely be cited. The S8 attribution should be reframed as spectral weight redistribution consistent with a surface species, supported by an S2p doublet decomposition, an independently constrained coverage, and ideally an interacting calculation. Without that, the "shift" claim should not stand as a band-structure effect.

Referee Report

3 major / 3 minor

Summary. The paper reports standing-wave photoemission electron microscopy (SW-PEEM) of monolayer WS2 transferred onto a W/C multilayer mirror substrate. Photon-energy-dependent W 4f, S 2p, and C 1s yield curves are fitted with the YXRO X-ray optical code to obtain a structural model (vdW gap 5 Å, WS2 thickness 3.97 Å, S-plane widths 1.41 Å, C cap 47.4 Å). The fitted model is used to compute E2 field profiles, which the authors interpret as giving enhanced sensitivity to the bottom sulfur layer at 630 eV and to the top sulfur layer at 680 eV. Valence-band spectra at these two energies show a relative shift of about 0.2 eV in sulfur-derived spectral weight, which the authors attribute to sulfur-related surface species (modeled as S8) rather than to substrate hybridization, on the basis of S 2p core-level data and DFT calculations. The paper claims that SW-PEEM establishes Å-scale depth-resolved spectromicroscopy of 2D materials.

Significance. If the central claim holds, SW-PEEM would be a valuable non-destructive probe of depth-dependent electronic structure in van der Waals materials, potentially resolving top versus bottom chalcogen states within a single monolayer. The experimental methodology—combining standing-wave photoemission with X-ray optical fitting—is demonstrated on a relevant 2D system, and the structural model is internally cross-checked with AFM step height and prior reports. The internal consistency check that the C 2sp feature is enhanced at 630 eV where the antinode lies in the carbon cap is a genuine positive control. However, the new physical conclusion—that sulfur-related surface species shift the top-sulfur valence band by ~0.2 eV—is not supported by the DFT calculation as presented, because the calculation is explicitly constructed as a non-interacting superposition. This limits the strength of the central claim and requires either additional calculation or a reframing of the conclusion.

major comments (3)

[Supporting Information, 'S8 on WS2' (p. 4-5); Fig. 3f] The DFT calculation supporting the central attribution places S8 7.5 Å above WS2 'in order to eliminate bonding interactions between WS2 and S8' and states that the total DOS is 'well approximated by the sum.' The ~0.2 eV shift in Fig. 3f is therefore a centroid shift produced by adding non-interacting S8 spectral weight to the sulfur-projected DOS; it is not a shift of the WS2-derived S 3sp states. The main-text claim that inclusion of S8 'produces a shift of ~0.2 eV toward the Fermi level' and the abstract's language 'consistent with sulfur-related surface species' overstate what the model can support. Because the 680-eV experimental spectrum also shows enhanced S8-related S2p weight near 163.5 eV (Fig. 3d), the observed valence-band change is equally explainable as a superposition of S8 states riding on the WS2 spectrum, with no actual binding-energy shift. Please either perform an in
[Fig. 2e; §'The fitted structural parameters'] The top/bottom S assignment of the 630/680 eV valence-band spectra relies entirely on the YXRO-fitted structural parameters—vdW gap 5.00 Å, WS2 thickness 3.97 Å, S-plane photoemitting widths 1.41 Å, C cap 47.40 Å—but no uncertainties, confidence intervals, or uniqueness tests are reported. The E2 profiles in Figs. 3a-b are forward calculations from these fitted values; if the fit is degenerate or the assumed layer-roughness/flake-waviness treatment is inadequate, the 'bottom S' and 'top S' labels collapse. Please provide parameter uncertainties and a sensitivity analysis (e.g., varying the vdW gap and S-plane widths within physically plausible ranges and recomputing the top/bottom enhancement ratio at 630 and 680 eV).
[Fig. 3c; text after 'In addition to the depth-dependent modulation'] The reported ~0.2 eV shift is not substantiated by a quantitative analysis. No fitting procedure, line-shape model, error bars, or statistical comparison of the 630 eV and 680 eV valence-band spectra is described for the S 3sp feature. Given that the two spectra contain different relative C 2sp and S8 contributions, the shift should be quantified with an explicit method and uncertainty to support the claim.

minor comments (3)

[Abstract and main text] The phrase 'Ångstrom-scale' is used; the correct symbol is Ångström (with an umlaut). Please update throughout.
[§'The fitted structural parameters'] The text says 'the theoretically predicted value (3.42 Å)' for the vdW gap, but this value comes from the DFT calculation using a 4×4 graphene model of the substrate, not from the actual W/C multilayer. Please clarify that the comparison is to a model substrate.
[Fig. 3d] The S 2p spectra would be easier to evaluate if the raw data points and fit components were shown separately, including the 163.5 eV component and the Shirley background, rather than only the summed spectra.

Circularity Check

1 steps flagged · score 6.0 of 10

S8 attribution of the 0.2 eV valence-band shift is a superposition artifact: the DFT model deliberately places S8 non-interacting, so the reproduced shift is a centroid change from added S8 DOS, not a band shift.

self definitional [Main text, paragraph beginning 'Having ruled out strong substrate-induced coupling...' (Fig. 3e-f); SI 'Figure S3: S8 on WS2']
"Inclusion of S8 enhances the sulfur-projected density of states and produces a shift of ~0.2 eV toward the Fermi level, capturing the direction and approximate magnitude of the experimentally observed shift within the calculational uncertainty (see Figure 3f)."

The S8 model is built to be non-interacting: the SI states the calculation was 'performed at an interlayer distance of 7.5 Å in order to eliminate bonding interactions between WS2 and S8' and that the total DOS 'is well approximated by the sum of the individual WS2 and S8 contributions.' Adding any S-derived molecular DOS in the S 3sp energy window shifts the sulfur-projected centroid toward lower binding energy by construction; this is a spectral-weight addition, not a change in WS2 band structure. The S8 species is already inferred from the same experimental S2p weight at ~163.5 eV, and the amount/broadening is chosen (1 S8 per 5×5 supercell), so the 'prediction' cannot independently confirm the attribution.

full rationale

The experimental core of the paper—SW-PEEM spectra at 630 eV vs 680 eV showing a ~0.2 eV valence-band difference and enhanced S2p weight near 163.5 eV—is empirical and not circular. The YXRO structural fit and E2 field profiles are derived from core-level yield curves and are model-based, but they do not use the target physical conclusion as an input; the depth-selectivity assignment is a self-consistent interpretation rather than a circular reduction. The main circularity is in the S8 support: the DFT model is deliberately arranged to be non-interacting, so the total DOS is a sum of WS2 and S8 contributions. The resulting ~0.2 eV shift is therefore a centroid shift caused by adding S8 spectral weight, and its magnitude is tied to the unconstrained choice of one S8 molecule per 5×5 supercell and the applied broadening. The paper presents this calculation as support for the claim that sulfur species shift the top-sulfur valence band, but the calculation only shows that adding S8-like states near the Fermi level moves the weighted centroid by ~0.2 eV—a mathematically forced outcome. The consistency loop is completed by using the 163.5 eV S2p feature to motivate S8 and then using the non-interacting S8 DOS to 'reproduce' the valence-band shift. No load-bearing circular self-citation chain is present: the standing-wave technique citations (Refs 11,12,15,21,30) are external or methodological and do not themselves encode the S8 conclusion. Because the central attribution is partially circular while the depth-resolved measurement is independent, a score of 6 is appropriate.

Assumptions & free parameters 6 free parameters · 4 assumptions · 1 invented entities

The central claims rest on (i) the YXRO structural fit parameters, which carry no reported uncertainties; (ii) the S8 coverage and non-interacting placement chosen in the DFT comparison, which control the computed shift magnitude; and (iii) standard DFT and X-ray-optics domain assumptions. No new physical entities are introduced — S8 is a known allotrope invoked as a 'representative elemental-sulfur model,' with the 163.5 eV S2p feature as an independent (but doublet-overlapping) observable.

free parameters (6)

vdW gap between WS2 and C capping layer = 5.00 Å (theory 3.42 Å)
Fitted in the YXRO simultaneous optimization; the top/bottom-S selectivity profile depends on this value, and its deviation from theory is attributed to impurities/waviness.
WS2 layer photoemitting widths (S planes, W plane) = S planes 1.41 Å each; W plane 1.15 Å; total 3.97 Å
Fitted to the W4f and S2p yield curves; these widths set the depth distribution used to compute the 63.5% vs 80% E2 contrast.
W/C multilayer parameters (period, C cap, W layer thickness) = period 35.8 Å; C cap 47.4 Å; W layer 15.0 Å
Fitted simultaneously; consistent with nominal XRD calibration (36 Å). C cap thickness was chosen to suppress substrate W4f.
S8 coverage in DFT comparison model = 1 S8 per 5x5 WS2 supercell
Chosen to avoid lateral S8-S8 interaction, not measured; the computed ~0.2 eV shift scales with this coverage.
S8–WS2 vertical separation in DFT = 7.5 Å (equilibrium found 2.7±0.4 Å)
Deliberately non-interacting so the DOS is a sum; makes the shift a weighted-centroid effect rather than a bonding shift.
Gaussian/Lorentzian broadening and cross-section weighting in spectral comparison = not specified numerically
Applied to computed spectra for comparison with experiment; the apparent width and shift of the summed DOS depend on these.

assumptions (4)

domain assumption PBE+DFT-D3 with PAW pseudopotentials describes the WS2 band structure, S8 levels, and the graphene/WS2 interface adequately for 0.2 eV-level comparison
Standard practice (VASP, PBE, DFT-D3), but PBE underestimates gaps and the substrate model uses a 4% strained 4x4 graphene/3x3 WS2 supercell as a proxy for amorphous carbon (SI Fig. S1-S2).
domain assumption YXRO X-ray optical model correctly computes the standing-wave E2 field and photoemission yields for the W/C multilayer at 580-720 eV
Relies on refs 14,15,21; the model is community-standard but not re-derived here, and the fitted parameters carry no uncertainty.
ad hoc to paper The extra S2p weight near 163.5 eV in the surface-sensitive spectrum indicates elemental-sulfur-like (S8) species
The cited elemental-S range is 163.6-164.2 eV, the observed enhancement is 'near 163.5 eV', and no S2p doublet decomposition isolates the component from bulk WS2 2p1/2.
domain assumption Cross-section, IMFP, and matrix-element differences between 630 eV and 680 eV do not produce the observed 0.2 eV shift
Argued qualitatively (p. 12) with refs 31,32; no quantitative line-shape calculation is provided.

invented entities (1)

Elemental-sulfur (S8-like) surface species on monolayer WS2 independent evidence
purpose: Postulated surface contaminant explaining the surface-sensitive S2p weight near 163.5 eV and the ~0.2 eV top-S valence-band shift
S8 is a known molecule, not an invented entity, but its presence on this sample is postulated; the 163.5 eV S2p feature is a falsifiable handle, though it overlaps the WS2 S2p1/2 line, weakening the constraint.

how reviews work

0 comments

Cite this review

Pith. "Pith review of Imaging of van der Waals Materials via Standing-Wave Photoemission Microscopy: Depth-Resolved Electronic Structure of WS2." pith.science (2026). https://pith.science/paper/PVYQQTO4

@misc{pith2026260723073,
  author       = {Pith},
  title        = {Pith review of: Imaging of van der Waals Materials via Standing-Wave Photoemission Microscopy: Depth-Resolved Electronic Structure of WS2},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/PVYQQTO4}},
  note         = {Machine review of arXiv:2607.23073}
}

read the original abstract

Two-dimensional van der Waals materials promise electronic, optoelectronic, and quantum technologies, yet depth-resolved characterization remains challenging. Here, we demonstrate standing-wave photoemission electron microscopy (SW-PEEM) for Angstrom-scale spectromicroscopy of monolayer WS2 on a W/C multilayer substrate. Tuning the X-ray standing wave through the monolayer yields a chemical depth profile and valence-band modulation with enhanced sensitivity to the top and bottom sulfur layers. X-ray optical modeling determines the structure and field distribution. The measurements reveal an ~0.2 eV shift in sulfur-derived valence-band spectral weight between measurements with enhanced sensitivity to the top and bottom sulfur layers. This shift is unlikely to arise from strong direct substrate hybridization and is instead consistent with sulfur-related surface species, as supported by calculations using a representative elemental-sulfur model. These results establish SW-PEEM as a non-destructive depth-resolved probe, highlighting its potential to probe interfacial coupling, chemical reconstruction, and emergent states in van der Waals and moir\'e systems.

Discussion (0). Continue with ORCID to comment.

Reference graph

Works this paper leans on

10 extracted references

[1]

From ultrasoft pseudopotentials to the projector augmented-wave method

Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 1999, 59, 1758

1999
[2]

Ab initio molecular dynamics for liquid metals

Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 1993, 47, 558

1993
[3]

Ab initio molecular -dynamics simulation of the liquid -metal–amorphous- semiconductor transition in germanium

Kresse, G.; Hafner, J. Ab initio molecular -dynamics simulation of the liquid -metal–amorphous- semiconductor transition in germanium. Phys. Rev. B 1994, 49, 14251

1994
[4]

Efficiency of ab -initio total energy calculations for metals and semiconductors using a plane-wave basis set

Kresse, G.; Furthmüller, J. Efficiency of ab -initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15

1996
[5]

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set

Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 1996, 54, 11169

1996
[6]

P.; Burke, K.; Ernzerhof, M

Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 1996, 77, 3865. 6

1996
[7]

A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT -D3) for the 94 elements H -Pu

Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT -D3) for the 94 elements H -Pu. J. Chem. Phys. 2010, 132, 154104

2010
[8]

B.; Ng, M

Yang, G.; Li, L.; Lee, W. B.; Ng, M. C. Structure of graphene and its disorders: a review. Sci. Technol. Adv. Mater. 2018, 19, 613

2018

Show all 10 references

[9]

J.; De Boer, J

Schutte, W. J.; De Boer, J. L.; Jellinek, F. Crystal structures of tungsten disulphide and diselenide. J. Solid State Chem. 1987, 70, 207

1987
[10]

VESTA 3 for three -dimensional visualization of crystal, volumetric and morphology data

Momma, K.; Izumi, F. VESTA 3 for three -dimensional visualization of crystal, volumetric and morphology data. J. Appl. Crystallogr. 2011, 44, 1272

2011

Pith tools

Reviewed August 1, 2026 · model on record in the stance chip above.

[1] [1]

From ultrasoft pseudopotentials to the projector augmented-wave method

Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 1999, 59, 1758

1999

[2] [2]

Ab initio molecular dynamics for liquid metals

Kresse, G.; Hafner, J. Ab initio molecular dynamics for liquid metals. Phys. Rev. B 1993, 47, 558

1993

[3] [3]

Ab initio molecular -dynamics simulation of the liquid -metal–amorphous- semiconductor transition in germanium

Kresse, G.; Hafner, J. Ab initio molecular -dynamics simulation of the liquid -metal–amorphous- semiconductor transition in germanium. Phys. Rev. B 1994, 49, 14251

1994

[4] [4]

Efficiency of ab -initio total energy calculations for metals and semiconductors using a plane-wave basis set

Kresse, G.; Furthmüller, J. Efficiency of ab -initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15

1996

[5] [5]

Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set

Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 1996, 54, 11169

1996

[6] [6]

P.; Burke, K.; Ernzerhof, M

Perdew, J. P.; Burke, K.; Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 1996, 77, 3865. 6

1996

[7] [7]

A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT -D3) for the 94 elements H -Pu

Grimme, S.; Antony, J.; Ehrlich, S.; Krieg, H. A consistent and accurate ab initio parametrization of density functional dispersion correction (DFT -D3) for the 94 elements H -Pu. J. Chem. Phys. 2010, 132, 154104

2010

[8] [8]

B.; Ng, M

Yang, G.; Li, L.; Lee, W. B.; Ng, M. C. Structure of graphene and its disorders: a review. Sci. Technol. Adv. Mater. 2018, 19, 613

2018