非线性电流诱导轨道磁化的量子几何起源
Quantum Geometric Origin of Nonlinear Current Induced Orbital Magnetization
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中文总结 AI 辅助
该研究针对非线性电流诱导轨道磁化的理论挑战，通过微观推导构建理论，结合第一性原理计算预测特定材料中存在显著非线性轨道磁化，其量子几何起源与两类极化率相关且可主导自旋对应物。
中文摘要 AI 辅助
电致磁化是凝聚态研究的重点，近期已推进至非线性 regime。但由于轨道磁性的非局域特性，如何恰当构建非线性电流诱导轨道磁化的理论仍是基础挑战。本文针对该效应构建了恰当理论，其基于布洛赫电子场修正轨道磁矩的微观推导，这是现有理论中关键缺失的部分。研究表明，该现象的量子几何起源既在于反常轨道极化率，也在于 Berry 连接极化率，二者常提供竞争贡献。结合该理论与第一性原理计算，预测在应变双层石墨烯、单层1T'相MoS₂和MoTe₂中可产生显著的、实验可及的非线性轨道磁化。值得注意的是，在具有拓扑能带特征的材料中，无论自旋轨道耦合强度如何，非线性轨道磁化均可在自旋对应物中占据主导地位。
英文摘要
Electric generation of magnetization is a focus of condensed matter research, and has recently been advanced into the nonlinear regime. However, due to the nonlocal nature of orbital magnetism, how to properly formulate nonlinear current-induced orbital magnetization remains a fundamental challenge. Here, we develop the proper theory for this effect. This is based on the microscopic derivation of field-corrected orbital magnetic moment of a Bloch electron, a critical missing piece in the present theory. We show that the quantum geometric origin of this phenomenon lies in both the anomalous orbital polarizability and the Berry-connection polarizability, which often provide competing contributions. Combining our theory with first-principles calculations, we predict significant, experimentally accessible nonlinear orbital magnetization generated in strained bilayer graphene, monolayer 1T' $\mathrm{MoS_2}$ and $\mathrm{MoTe_2}$. Remarkably, nonlinear orbital magnetization can dominate over its spin counterpart in materials with topological band features, irrespective of the spin-orbit coupling strength.
