A detailed electronic structure study of Vanadium metal by using different beyond-DFT methods

Sihi, Antik; Pandey, Sudhir K.

doi:10.1140/epjb/e2019-100500-8

Cited by 23 publications

(17 citation statements)

References 62 publications

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“…Therefore in this context, it is interesting to investigate that if one moves form SnS to SnSe then whether the strength of correlation within the sample is also changing or not. The correlation strength along with the presence of plasmon excitation can be possibly estimated from the frequency (ω) dependent W [18][19][20][21][22] . Also, the comparative studies of many-body interactions using full-GW method may illustrate more clear view of electronic structure's properties of these two materials.…”

Section: Introductionmentioning

confidence: 99%

Exploring temperature dependent electron-electron interaction of topological crystalline insulators (SnS and SnSe) within Matsubara-time domain

Sihi,

Pandey

2022

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Both experimental and theoretical studies show non-trivial topological behaviour in native rocksalt phase for SnS and SnSe and categorize these materials in topological crystalline insulators. Here, the detailed electronic structures studies of SnS and SnSe in the rocksalt phase are carried out using many-body GW based theory and density functional theory both for ground states and temperature dependent excited states. The estimated values of fundamental direct bandgaps around L-point using G0W0 (mBJ) are ∼0.27 (∼0.13) eV and ∼0.37 (∼0.17) eV for SnS and SnSe, respectively. The strength of hybridization between Sn 5p and S 3p (Se 4p) orbitals for SnS (SnSe) shows strong k-dependence. The behaviour of W (ω), which is the averaged value of diagonal matrix elements of fully screened Coulomb interaction, suggests to use full-GW method for exploring the excited states because the correlation effects within these two materials are relatively weak. The temperature dependent electronic structure calculations for SnS and SnSe provide linearly decreasing behaviour of bandgaps with rise in temperatures. The existence of collective excitation of quasiparticles in form of plasmon is predicted for these compounds, where the estimated values of plasmon frequency are ∼9.5 eV and ∼9.3 eV for SnS and SnSe, respectively. The imaginary part of self-energy and mass renormalization factor (Z k (ω)) due to electron-electron interaction (EEI) are also calculated along W-L-Γ direction for both the materials, where the estimated ranges of Z k (ω) are 0.70 to 0.79 and 0.71 to 0.78 for SnS and SnSe, respectively, along this k-direction. The present comparative study reveals that the behaviour of temperature dependent EEI for SnS and SnSe are the almost same and EEI is important for high temperature transport properties.

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Section: Introductionmentioning

confidence: 99%

Exploring temperature dependent electron-electron interaction of topological crystalline insulators (SnS and SnSe) within Matsubara-time domain

Sihi,

Pandey

2022

Preprint

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“…The imaginary part of self-energy gives a picture of strength of interaction between carriers. The electronic structure and strength of EEI in solids is normally studied using GW or DFT + dynamical mean field theory (DMFT) methods [21][22][23]. The electron-phonon matrix elements can be calculated under combined density functional perturbation theory (DFPT) and using Wannier functions for interpolation method [24].…”

Section: Introductionmentioning

confidence: 99%

Studying the lifetime of charge and heat carriers due to intrinsic scattering mechanisms in FeVSb half-Heusler thermoelectric

Shastri¹,

Pandey²

2021

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This work, presents a study of lifetime of carriers due to intrinsic scattering mechanisms viz. electron-electron (EEI), electron-phonon (EPI) and phonon-phonon interactions (PPI) in a promising half-Heusler thermoelectric FeVSb. Using the full-GW method, the effect of EEI and temperature on the valence and conduction band extrema and band gap are studied. The lifetime of carriers with temperature are estimated at these band extrema. At 300 K, estimated value of lifetime at VBM (CBM) is ∼1.91 x10 −14 s (∼2.05 x10 −14 s). The estimated ground state band gap considering EEI is ∼378 meV. Next, the effect of EPI on the lifetime of electrons and phonons with temperature are discussed. The comparison of two electron lifetimes suggests that EEI should be considered in transport calculations along with EPI. The average acoustic, optical and overall phonon lifetimes due to EPI are studied with temperature. Further, the effect of PPI is studied by computing average phonon lifetime for acoustic and optical phonon branches. The lifetime of the acoustic phonons are higher compared to optical phonons which indicates acoustic phonons contribute more to lattice thermal conductivity (κ ph ). The comparison of phonon lifetime due to EPI and PPI suggests that, above 500 K EPI is the dominant phonon scattering mechanism and cannot be ignored in κ ph calculations. Lastly, a prediction of the power factor and figure of merit of n-type and p-type FeVSb is made by considering the temperature dependent carrier lifetime for the electronic transport terms. This study shows the importance of considering EEI in electronic transport calculations and EPI in phonon transport calculations. Our study is expected to provide results to further explore the thermoelectric transport in this material.

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“…The strength of electronic correlation effect of any material can be estimated from the frequency (ω) dependent W 13 , which also provides the information about plasmon excitation [14][15][16][17] . Nowadays, different many-body techniques (i.e.…”

Section: Introductionmentioning

confidence: 99%

Investigating the effect of temperature dependent many-body interactions on bulk electronic structures and the robust nature of (001) surface states of SnTe

Sihi,

Pandey

2020

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Recently, SnTe has gained attention due to its non-trivial topological nature and eco-friendly thermoelectric applications. We report a detailed temperature dependent electronic structure and thermodynamic properties of this compound using DFT and GW methods. The calculated values of bandgaps by using PBEsol and G0W0 methods are found to be in good agreement with the experiment, whereas mBJ underestimates the bandgap. The estimated value of fully screened Coulomb interaction (W ) for Sn (Te) 5p orbitals is ∼1.39 (∼1.70) eV. The nature of frequency dependent W reveals that the correlation strength of this compound is relatively weaker and hence the excited electronic state can be properly studied by full-GW many-body technique. The plasmon excitation is found to be important in understanding this frequency dependent W . In order to describe the experimental phonon modes, the long range Coulomb forces using nonanalytical term correction is considered. The temperature dependent electron-electron interactions (EEI) reduces the bandgaps with increasing temperature. The value of bandgap at 300 K is obtained to be ∼161 meV. The temperature dependent lifetimes of electronic state along W-L-Γ direction are also estimated. This work suggests that EEI is important to explain the high temperature transport behaviour of SnTe. We have also explored the possibility of protecting the (001) surface states via mirror and time-reversal symmetry. These surface states are expected to be robust against the point and line defects.Recently, the effect of temperature on electronic struc-

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A detailed electronic structure study of Vanadium metal by using different beyond-DFT methods

Cited by 23 publications

References 62 publications

Exploring temperature dependent electron-electron interaction of topological crystalline insulators (SnS and SnSe) within Matsubara-time domain

Exploring temperature dependent electron-electron interaction of topological crystalline insulators (SnS and SnSe) within Matsubara-time domain

Studying the lifetime of charge and heat carriers due to intrinsic scattering mechanisms in FeVSb half-Heusler thermoelectric

Investigating the effect of temperature dependent many-body interactions on bulk electronic structures and the robust nature of (001) surface states of SnTe

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