Title: Electronic structure of chromium trihalides beyond density functional theory

Abstract

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.

Authors:

Acharya, Swagata  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8074-0030"

Pashov, Dimitar ^[2]; Cunningham, Brian  ^[3];

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Rudenko, Alexander N.  ^[1];

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Rösner, Malte  ^[1];

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Grüning, Myrta ^[4]; van Schilfgaarde, Mark ^[5]; Katsnelson, Mikhail I.  ^[1]

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• Search DOE PAGES for ORCID "0000-0001-5165-7553"

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+ Show Author Affiliations

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)

Publication Date:

Tue Oct 05 00:00:00 EDT 2021

Research Org.:

National Renewable Energy Lab. (NREL), Golden, CO (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE)

OSTI Identifier:

1832421

Report Number(s):

NREL/JA-5F00-81488
Journal ID: ISSN 2469-9950; MainId:82261;UUID:c396890b-063e-47bd-90d2-8442b15eb7f7;MainAdminID:63317; TRN: US2216744

Grant/Contract Number:  

AC36-08GO28308

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review B

Additional Journal Information:

Journal Volume: 104; Journal Issue: 15; Journal ID: ISSN 2469-9950

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

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