报告题目：Nonlinear electric transports

报告人：何攀，复旦大学

时间地点：2023-03-21 周二上午10点，理科楼C302报告厅

Abstract: So far, exotic transports arising from time reversal or spatial inversion symmetry breaking have been studied mainly in linear regimes. Nonlinear electric transports, which contain different information than their linear counterparts, have recently attracted increasing interest in homogeneous materials without conventional p-n junctions. In particular, the second-order nonlinear transports have been widely studied in quantum materials with broken inversion symmetry, including nonlinear magnetoresistance and nonlinear Hall effect. In this talk, I will first present our discovery of a spin-dependent nonlinear magnetoresistance1，which allowed us to detect a three-dimensional spin texture in momentum space by transport measurements2. In the second part, I will present our recent work on nonlinear Hall effects3-5. We discovered the nonlinear planar Hall effect3, arising from the conversion of nonlinear spin current to charge current under the action of a magnetic field. We demonstrated the nonlinear Hall effect at zero magnetic field due to skew scattering of chiral electron wavefunction4, and observed a giant nonlinear Hall conductivity in the graphene moiré superlattice5. If time permits, I will present some of our ongoing work.

References:

1.P. He, et al. Nature Phys., 14, 495 (2018)

2.P. He, et al. Phys. Rev. Lett., 120, 266802 (2018)

3.P. He, et al. Phys. Rev. Lett., 123, 016801 (2019)

4.P. He, et al. Nature Commun., 12, 698 (2021)

5.P. He, et al. Nature Nanotechnol., 17, 378 (2022)

个人简介：何攀，青年研究员，博士生导师。2008年在上海大学物理系获学士学位，2014年在复旦大学物理学系获博士学位。2014-2015年在法国国家科学研究中心从事博士后研究；2015-2020年在新加坡国立大学任研究员/高级研究员；2020年9月加入复旦大学微纳电子器件与量子计算机研究院工作至今。入选国家青年人才计划和上海市海外高层次人才计划。何攀研究员长期从事磁性和自旋电子学的实验研究，近期的研究兴趣是非线性量子输运。目前在Nature Physics，Nature Nanotechnology，Physical Review Letters，Nature Communications等学术期刊上共发表论文30余篇。