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arXiv 2402.12918cond-mat.str-elcond-mat.mtrl-sci
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重过渡金属化合物中具有大电荷能隙的反铁磁陈绝缘体

Antiferromagnetic Chern insulator with large charge gap in heavy transition-metal compounds

Mohsen Hafez-Torbati, Götz S. Uhrig

AI总结:

本文通过Kane-Mele-Kondo模型研究重过渡金属化合物中的反铁磁陈绝缘体,发现适中的自旋轨道耦合和交替子晶格势可稳定电荷能隙高达300 meV的AFCI,并据此解释了CrO和MoO单层中的实验结果,同时提出钙钛矿氧化物双层有望实现室温AFCI。

摘要:

尽管近年来发现了多种本征磁性拓扑绝缘体,但由于电荷能隙极小,陈绝缘体的观测仍仅限于极低温度。在此,我们揭示了重过渡金属化合物在实现具有高达300 meV电荷能隙的共线反铁磁陈绝缘体(AFCI)方面的潜力。我们的分析基于Kane-Mele-Kondo模型,该模型中巡游电子自旋与大小为$S$的局域自旋之间存在铁磁洪德耦合$J_{\rm H}$。我们证明,只要交替子晶格势$δ$处于$δ\approx SJ_{\rm H}$范围内,自旋轨道耦合$λ_{\rm SO} \gtrsim 0.03t$(其中$t$为最近邻跃迁参数)就足以稳定AFCI。我们发现在AFCI相中,电荷能隙随$λ_{\rm SO}$增大而显著增加。利用这些结果,我们解释了最近在CrO和MoO单层中发现的共线AFCI,其电荷能隙分别为1 meV和$50$ meV。此外,我们提出,若沿$[111]$方向生长并施加垂直电场,钙钛矿结构的重过渡金属氧化物双层有望成为实现室温AFCI的候选体系。

英文摘要:

Despite the discovery of multiple intrinsic magnetic topological insulators in recent years the observation of Chern insulators is still restricted to very low temperatures due to the negligible charge gaps. Here, we uncover the potential of heavy transition-metal compounds for realizing a collinear antiferromagnetic Chern insulator (AFCI) with a charge gap as large as 300 meV. Our analysis relies on the Kane-Mele-Kondo model with a ferromagnetic Hund coupling $J_{\rm H}$ between the spins of itinerant electrons and the localized spins of size $S$. We show that a spin-orbit coupling $λ_{\rm SO} \gtrsim 0.03t$, where $t$ is the nearest-neighbor hopping element, is already large enough to stabilize an AFCI provided the alternating sublattice potential $δ$ is in the range $δ\approx SJ_{\rm H}$. We establish a remarkable increase in the charge gap upon increasing $λ_{\rm SO}$ in the AFCI phase. Using our results we explain the collinear AFCI recently found in monolayers of CrO and MoO with charge gaps of 1 and $50$ meV, respectively. In addition, we propose bilayers of heavy transition-metal oxides of perovskite structure as candidates to realize a room-temperature AFCI if grown along the $[111]$ direction and subjected to a perpendicular electric field.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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