Sensitivity of the Fermi surface to the treatment of exchange and correlation

Harris-Lee, Eddie I; James, Alyn D. N.; Dugdale, Stephen B

doi:10.1103/physrevb.103.235144

“…The possibility of this behavior being an artifact of the reconstruction was excluded by reconstructing the 2D LCW from theoretically calculated 1D Compton profiles (top right), which did not show a dip in the center of the LCW. Typically, theoretical calculations using the LDA or GGA are not fully capable of reproducing all parts of the Fermi surface equally well [60]. From our Fermi surface calculations (Fig.…”

Section: B 2d Reconstruction From 1d-compton Profilesmentioning

confidence: 95%

Momentum density spectroscopy of Pd: Comparison of 2D-ACAR and Compton scattering using a 1D-to-2D reconstruction method

Ketels

¹

,

Billington²,

Dugdale³

et al. 2021

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Two-dimensional (2D) angular correlation of annihilation radiation and Compton scattering are both powerful techniques to investigate the bulk electronic structure of crystalline solids through the momentum density of the electrons. Here we apply both methods to a single crystal of Pd to study the electron momentum density and the occupancy in the first Brillouin zone and to point out the complementary nature of the two techniques. To retrieve the 2D spectra from one-dimensional Compton profiles, a direct inversion method is implemented and benchmarked against the well-established Cormack's method. The comparison of experimental spectra with first-principles density functional theory calculations of the electron momentum density and the two photon momentum density clearly reveals the importance of positron probing effects on the determination of the electronic structure. While the calculations are in good agreement with the experimental data, our results highlight some significant discrepancies.

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“…The disagreement in the occupancy may stem from inadequacies in the description of the hybridisation between the Cr 3d and Pd 4d states (which relates to the interlayer electron coupling) at the DFT level. This can be very sensitive to the exchange-correlation functional used at the DFT level, as seen for group V and VI elements [44]. Considering that the Pd states are primarily treated on the DFT level, higher order electron correlation contributions may influence the Pd conduction quasiparticle band dispersion and impact the inter-layer electron coupling.…”

Section: Resultsmentioning

confidence: 99%

Impact of electron correlations on the $\mathbf{k}$-resolved electronic structure of PdCrO$_{2}$ revealed by Compton scattering

James¹,

Billington²,

Dugdale³

2023

Preprint

0

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Delafossite PdCrO2 is an intriguing material which displays nearly-free electron and Mott insulating behaviour in different layers. Both angle-resolved photoemission spectroscopy (ARPES) and Compton scattering measurements have established a hexagonal Fermi surface in the material's paramagnetic phase. However, the Compton experiment detected an additional structure in the projected occupancy which was originally interpreted as an additional Fermi surface feature not seen by ARPES. Here, we revisit this interpretation of the Compton data. State-of-the-art density functional theory (DFT) with dynamical mean field theory (DMFT), the so-called DFT+DMFT method, predicts the Mott insulating state along with a single hexagonal Fermi surface in excellent agreement with ARPES and Compton. However, DFT+DMFT fails to predict the intensity of the additional spectral weight feature observed in the Compton data. We infer that this discrepancy may arise from the DFT+DMFT not being able to correctly predict certain features in the shape and dispersion of the unoccupied quasiparticle band near the Fermi level. Therefore, a theoretical description beyond our DFT+DMFT model is needed to incorporate vital electron interactions, such as inter-layer electron coupling interactions which for PdCrO2 gives rise to the Kondo-like so-called intertwined excitation.

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“…The disagreement in the occupancy may stem from inadequacies in the description of the hybridisation between the Cr 3d and Pd 4d states (which relates to the inter-layer electron coupling) at the DFT level. This can be very sensitive to the exchange-correlation functional used at the DFT level, as seen for group V and VI elements [44]. Considering that the Pd states are primarily treated on the DFT level, higher order electron correlation contributions may influence the Pd conduction quasiparticle band dispersion and impact the inter-layer electron coupling.…”

Section: Resultsmentioning

confidence: 99%

Impact of electron correlations on the k-resolved electronic structure of PdCrO₂ revealed by Compton scattering

James

¹

,

Billington

²

,

Dugdale

³

2023

Electron. Struct.

Self Cite

0

View full text Add to dashboard Cite

Delafossite PdCrO2 is an intriguing material which displays nearly-free electron and Mott insulating behaviour in different layers. Both angle-resolved photoemission spectroscopy (ARPES) and Compton scattering measurements have established a hexagonal Fermi surface in the material's paramagnetic phase. However, the Compton experiment detected an additional structure in the projected occupancy which was originally interpreted as an additional Fermi surface feature not seen by ARPES. Here, we revisit this interpretation of the Compton data. State-of-the-art density functional theory (DFT) with dynamical mean field theory (DMFT), the so-called DFT+DMFT method, predicts the Mott insulating state along with a single hexagonal Fermi surface in excellent agreement with ARPES and Compton. However, DFT+DMFT fails to predict the intensity of the additional spectral weight feature observed in the Compton data. We infer that this discrepancy may arise from the DFT+DMFT not being able to correctly predict certain features in the shape and dispersion of the unoccupied quasiparticle band near the Fermi level. Therefore, a theoretical description beyond our DFT+DMFT model is needed to incorporate vital electron interactions, such as inter-layer electron coupling interactions which for PdCrO2 gives rise to the Kondo-like so-called intertwined excitation.

show abstract

Sensitivity of the Fermi surface to the treatment of exchange and correlation

Cited by 5 publications

References 107 publications

Momentum density spectroscopy of Pd: Comparison of 2D-ACAR and Compton scattering using a 1D-to-2D reconstruction method

Momentum density spectroscopy of Pd: Comparison of 2D-ACAR and Compton scattering using a 1D-to-2D reconstruction method

Impact of electron correlations on the $\mathbf{k}$-resolved electronic structure of PdCrO$_{2}$ revealed by Compton scattering

Impact of electron correlations on the k-resolved electronic structure of PdCrO₂ revealed by Compton scattering

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Sensitivity of the Fermi surface to the treatment of exchange and correlation

Cited by 5 publications

References 107 publications

Momentum density spectroscopy of Pd: Comparison of 2D-ACAR and Compton scattering using a 1D-to-2D reconstruction method

Momentum density spectroscopy of Pd: Comparison of 2D-ACAR and Compton scattering using a 1D-to-2D reconstruction method

Impact of electron correlations on the $\mathbf{k}$-resolved electronic structure of PdCrO$_{2}$ revealed by Compton scattering

Impact of electron correlations on the k-resolved electronic structure of PdCrO2 revealed by Compton scattering

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Product

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About

Impact of electron correlations on the k-resolved electronic structure of PdCrO₂ revealed by Compton scattering