Weak localization is the quintessential quantum interference phenomenon that features prominently in disordered conductors. Since its discovery, the canonical diagnostic for electron weak localization in conductors has been the magnetoresistance, which works as a space-domain interferometry. In this work, we propose an ultrafast diagnostic for electron weak localization based on the nonlinear optical response in the terahertz regime. Our analytical and numericalcalculations reveal that, in orthogonal/symplectic class systems, two consecutive, phase coherent optical pulses generate an electric current echo that appears after the second pulse, and at a time equal to the pulse delay time. The current echo reflects the quantum interference between a self-intersecting electron path and its time reversal partner, and, therefore, provide a time-domain interferometry of weak localization. Our results can be potentially tested on disordered metal films by using terahertz two-dimensional coherent spectroscopy or ultrafast transport measurements.

报告人简介 

万源，中科院物理所凝聚态理论与计算实验室特聘研究员。2014美国约翰霍普金斯获哲学博士学位，2014年-2018年，先后在加拿大Perimeter Institute及牛津大学Rudolf Peierls理论物理研究中心从事博士后研究工作，2018年开始任中科院物理所副研究员。研究方向为凝聚态理论，近期的研究兴趣包括阻挫磁性、非平衡物理，以及拓扑序。

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田矗舜 研究员