发表机构
Kyoto University; The University of Tokyo（京都大学; 东京大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
结合绝热微扰论与非平衡格林函数方法，发现纵向非互易电流由量子度量偶极子主导，其物理起源是偏置场下电子波包弛豫时的有限展宽导致的准平衡位移。
AI 中文摘要
我们通过将绝热微扰论与非平衡格林函数方法相结合，研究了量子度量起源的非线性直流电输运。绝热假设为直接在速度规范下处理直流电场（而非将其引入为交流电场的零频极限）提供了基础。由此得到的绝热基哈密顿量具有与长度规范相同的形式，从而能够对不同公式进行系统比较。应用这种全量子公式，我们发现由量子度量偶极子控制的纵向非互易电流。其关键要素是分布函数中的量子修正，这在半经典处理中是不存在的。我们将这一修正追溯到偏置场下弛豫过程中电子波包的有限展宽，从而将位移的准平衡识别为量子度量非互易输运的物理起源。
英文摘要
We study nonlinear DC electric transport of quantum-metric origin by combining adiabatic perturbation theory with the nonequilibrium Green function approach. The adiabatic ansatz provides a basis for directly treating a DC electric field in the velocity gauge, rather than introducing it as the zero-frequency limit of an AC field. The resulting adiabatic-basis Hamiltonian takes the same form as in the length gauge, enabling a systematic comparison across different formulations. Applying this fully quantum formulation, we find a longitudinal nonreciprocal current governed by the quantum-metric dipole. The essential ingredient is a quantum correction to the distribution function that is absent in semiclassical treatments. We trace this correction to the finite spread of an electron wave packet during relaxation under a bias field, thereby identifying shifted quasiequilibrium as the physical origin of quantum-metric nonreciprocal transport.
Comments16 pages, 2 figures
