Quantum Anomalous Hall Effect in $d$-Electron Kagome Systems: Chern Insulating States from Transverse Spin-Orbit Coupling

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Main Authors: Makhfudz, Imam, Cherkasskii, Mikhail, Alipourzadeh, Mohammad, Hajati, Yaser, Lombardo, Pierre, Schäfer, Steffen, Kusminskiy, Silvia Viola, Hayn, Roland
Format: Preprint
Published: 2024
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author Makhfudz, Imam
Cherkasskii, Mikhail
Alipourzadeh, Mohammad
Hajati, Yaser
Lombardo, Pierre
Schäfer, Steffen
Kusminskiy, Silvia Viola
Hayn, Roland
author_facet Makhfudz, Imam
Cherkasskii, Mikhail
Alipourzadeh, Mohammad
Hajati, Yaser
Lombardo, Pierre
Schäfer, Steffen
Kusminskiy, Silvia Viola
Hayn, Roland
contents The possibility of quantum anomalous Hall effect (QAHE) in two-dimensional kagome systems with $d$-orbital electrons is studied within a multi-orbital tight-binding model. We concentrate on the case of isotropic Slater-Koster integrals which is realized in a recently discovered class of metal-organic frameworks TM$_3$C$_6$O$_6$ with transition metals (TM) in the beginning of the 3$d$ series. Furthermore, in the absence of exchange-type spin-orbit coupling, only isotropic Slater-Koster integrals give a perfect flatband in addition to the two dispersive bands hosting relativistic (Dirac) and quadratic band crossing points at high symmetry spots in the Brillouin zone. A quantized topological invariant requires a flux-creating spin-orbit coupling, giving Chern number (per spin sector) $C=1$ not only from the familiar Dirac points at the six corners of the Brillouin zone, but also from the quadratic band crossing point at the center $Γ$. In the case of isotropic Slater-Koster integrals the on-site spin-orbit coupling (SOC) is ineffective to create the QAHE and it is only the transfer or exchange-type SOC which can lead to a QAHE. Surprisingly, this QAHE comes from the nontrivial effective flux induced by the \textit{transverse} part of the spin-orbit coupling, exhibited by electrons in the $d$-orbital state with $m_l=0$ ($d_{z^2}$ orbital), in stark contrast to the more familiar form of QAHE due to the $d$-orbitals with $m_l \neq 0$, driven by the Ising part of spin-orbit coupling. The $C=1$ Chern plateau (per spin sector) due to Dirac point extends over a smaller region of Fermi energy than that due to quadratic band crossing. Our result hints at the promising potential of kagome $d$-electron systems as a platform for dissipationless electronics by virtue of its unique QAHE.
format Preprint
id arxiv_https___arxiv_org_abs_2402_05845
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum Anomalous Hall Effect in $d$-Electron Kagome Systems: Chern Insulating States from Transverse Spin-Orbit Coupling
Makhfudz, Imam
Cherkasskii, Mikhail
Alipourzadeh, Mohammad
Hajati, Yaser
Lombardo, Pierre
Schäfer, Steffen
Kusminskiy, Silvia Viola
Hayn, Roland
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
The possibility of quantum anomalous Hall effect (QAHE) in two-dimensional kagome systems with $d$-orbital electrons is studied within a multi-orbital tight-binding model. We concentrate on the case of isotropic Slater-Koster integrals which is realized in a recently discovered class of metal-organic frameworks TM$_3$C$_6$O$_6$ with transition metals (TM) in the beginning of the 3$d$ series. Furthermore, in the absence of exchange-type spin-orbit coupling, only isotropic Slater-Koster integrals give a perfect flatband in addition to the two dispersive bands hosting relativistic (Dirac) and quadratic band crossing points at high symmetry spots in the Brillouin zone. A quantized topological invariant requires a flux-creating spin-orbit coupling, giving Chern number (per spin sector) $C=1$ not only from the familiar Dirac points at the six corners of the Brillouin zone, but also from the quadratic band crossing point at the center $Γ$. In the case of isotropic Slater-Koster integrals the on-site spin-orbit coupling (SOC) is ineffective to create the QAHE and it is only the transfer or exchange-type SOC which can lead to a QAHE. Surprisingly, this QAHE comes from the nontrivial effective flux induced by the \textit{transverse} part of the spin-orbit coupling, exhibited by electrons in the $d$-orbital state with $m_l=0$ ($d_{z^2}$ orbital), in stark contrast to the more familiar form of QAHE due to the $d$-orbitals with $m_l \neq 0$, driven by the Ising part of spin-orbit coupling. The $C=1$ Chern plateau (per spin sector) due to Dirac point extends over a smaller region of Fermi energy than that due to quadratic band crossing. Our result hints at the promising potential of kagome $d$-electron systems as a platform for dissipationless electronics by virtue of its unique QAHE.
title Quantum Anomalous Hall Effect in $d$-Electron Kagome Systems: Chern Insulating States from Transverse Spin-Orbit Coupling
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2402.05845