Electronic structure of chromium trihalides beyond density functional theory

Journal Article · Tue Oct 05 00:00:00 EDT 2021 · Physical Review B

DOI:https://doi.org/10.1103/physrevb.104.155109· OSTI ID:1832421

Acharya, Swagata ^[1]; Pashov, Dimitar ^[2]; Cunningham, Brian ^[3]; Rudenko, Alexander N. ^[1]; Rösner, Malte ^[1]; Grüning, Myrta ^[4]; van Schilfgaarde, Mark ^[5]; Katsnelson, Mikhail I. ^[1]

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1. Radboud Univ., Nijmegen (Netherlands). Inst. for Molecules and Materials
2. King's College London (United Kingdom)
3. Queen's Univ., Belfast, Northern Ireland (United Kingdom). Centre for Theoretical Atomic, Molecular and Optical Physics
4. Queen's Univ., Belfast, Northern Ireland (United Kingdom). Atomistic Simulation Centre
5. King's College London (United Kingdom); National Renewable Energy Lab. (NREL), Golden, CO (United States)

In this work, we explore the electronic band structure of freestanding monolayers of chromium trihalides $\mathrm{Cr}{X}_3$ , $X$ = Cl, Br, I, within an advanced ab initio theoretical approach based on the use of Green's function functionals. We compare the local density approximation with the quasiparticle self-consistent GW (QSGW) approximation and its self-consistent extension $\left(\mathrm{QS}G\hat{W}\right)$ by solving the particle-hole ladder Bethe-Salpeter equations to improve the effective interaction $W$ . We show that, at all levels of theory, the valence band consistently changes shape in the sequence $\mathrm{Cl}\to \mathrm{Br}\to \mathrm{I}$ , and the valence band maximum shifts from the $M$ point to the $\mathrm{\Gamma }$ point. By analyzing the dynamic and momentum-dependent self-energy, we show that $\mathrm{QS}G\hat{W}$ adds to the localization of the systems in comparison with QSGW, thereby leading to a narrower band and reduced amount of halogens in the valence band manifold. Further analysis shows that $X$ = Cl is most strongly correlated, and $X$ = I is least correlated (most bandlike) as the hybridization between Cr $d$ and $X$ $p$ enhances in the direction $\mathrm{Cl}\to \mathrm{Br}\to \mathrm{I}$ . For ${\mathrm{CrBr}}_3$ and ${\mathrm{CrI}}_3$ , we observe remarkable differences between the QSGW and $\mathrm{QS}G\hat{W}$ valence band structures, while their eigenfunctions are very similar. We show that weak perturbations, like moderate strain, weak changes to the $d-p$ hybridization, and adding small $U$ , can flip the valence band structures between these two solutions in these materials.

• Research Organization: National Renewable Energy Laboratory (NREL), Golden, CO (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE)
• Grant/Contract Number: AC36-08GO28308
• OSTI ID: 1832421
• Report Number(s): NREL/JA--5F00-81488; MainId:82261; UUID:c396890b-063e-47bd-90d2-8442b15eb7f7; MainAdminID:63317
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 15 Vol. 104; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
Bethe-Salpeter equation
GW method
chromium compounds
eigenvalues and eigenfunctions
electronic structure
local density approximation
monolayer films
monolayers
valence bands