标题： 磁 Rashba 半导体 (Ge,Mn)Te 低能线性和非线性光学响应中的量子几何 显示英文标题

标题： Quantum geometry in low-energy linear and nonlinear optical responses of magnetic Rashba semiconductor (Ge,Mn)Te

摘要： 量子几何在理解量子材料的光学性质中起着关键作用，人们期望在狄拉克点和外尔点附近出现发散或量子化的响应。 在这里，我们研究了磁性Rashba半导体在中红外区域的线性和非线性光学响应——光学电导率和注入电流，并在狄拉克点附近改变费米能级。 我们发现，线性光学电导率反映了量子度量，即使在较低光子能量下联合态密度减小，它仍然保持有限。 还确认了磁性注入电流随着费米能级相对于狄拉克点的能量变化而增强。 这些光学谱图通过考虑几何效应的理论计算得到了很好的再现。 显示英文摘要

摘要： Quantum geometry appears as a key factor in understanding the optical properties of quantum materials, with the anticipation on diverging or quantized responses near the Dirac and Weyl points. Here we investigate linear and nonlinear optical responses-optical conductivity and injection current- in a magnetic Rashba semiconductor in the mid-infrared region, with varying the Fermi energy across the Dirac point. We reveal that the linear optical conductivity reflects quantum metric, which remains finite irrespective of the diminishing joint density-of-states at lower photon energy. It is also confirmed that the magnetic injection current enhances depending on the energy of the Fermi level relative to the Dirac point. These optical spectra are nicely reproduced by our theoretical calculations with geometrical effects taken into account.