Quant-ph 20181126 Quantum transport of two-dimensional non-equilibrium states under microwave irradiation

Title:Quantum transport of two-dimensional non-equilibrium states under microwave irradiation
Speaker:Prof. Chi Zhang
Time:10:30 November 26 (Monday), 2018
Place:TDLI Meeting Room 200 (East Wing of Pao Yue-kong Library)
Host:Prof. Jianda Wu


In high quality two-dimensional electron systems (2DES), novel electron states and phenomena can be revealed by microwave (MW) techniques. Microwave-induced resistance oscillations (MIRO) [1, 2] and the related zero-resistance states (ZRS) [3, 4], and Zener tunneling (or Hall-field induced resistance oscillations (HIRO)) [5] are novel phenomena in ultraclean 2DES. In this talk, I am going to present our work pertaining to these areas. (1) In the study of the quantum capacitances of MIRO/ZRS, the field penetration current results show that the quantum capacitance oscillates with MIRO, however, the trend is opposite with respect to the compressibility of usual equilibrium states in previous theoretical explanations. Moreover, the quantum capacitance indication for multi-photon process around j = 1/2 is detected under intensive microwave below 30 GHz. The anomalous phenomena provide a platform for study on the non-equilibrium system under microwave [6]. (2) Robust oscillations induced by multi-photon process, and Shubnikov-de Haas (SdH)-like oscillations (ac-HIRO) are observed under low frequency MW (f < 10 GHz). The oscillations of MIRO, dc-HIRO and ac-HIRO can be explained in the frame of tunneling junction model [7].
[1] M. A. Zudov, R. R. Du, J. A. Simmons, and J. L. Reno, Phys. Rev. B 64, 201311(R) (2001).
[2] P. D. Ye, L. W. Engel, D. C. Tsui, J. A. Simmons, J. R. Wendt, G. A. Vawter, and J. L. Reno, Appl. Phys. Lett. 79, 2193 (2001).
[3] R. G. Mani, Jurgen H. Smet, Klaus von Klitzing, Venkatesh Narayanamurti, William B. Johnson, and Vladimir Umansky, Nature 420, 646 (2002).
[4] M. A. Zudov, R. R. Du, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett. 90, 046807 (2003).
[5] C. L. Yang, J. Zhang, R. R. Du, J. A. Simmons, and J. L. Reno, Phys. Rev. Lett. 89, 076801 (2002).
[6] Jian Mi, Jianli Wang, Saeed Fallahi, Geoffrey C. Gardner, M. J. Manfra, Chi Zhang, arXiv: 1612.05196. (PRL under review).
[7] Jian Mi, Huiying Liu, Junren Shi, L. N. Pfeiffer, K. W. West, K. W. Baldwin, Chi Zhang, arXiv: 1708.08498.



Chi Zhang received his Bachelor degree of Physics from the University of Science and Technology of China (USTC) in 2004. In 2010, he received his Ph. D. of Physics from Rice University. Dr. Zhang worked as a post-doctoral researcher at the Department of Electric Engineering at Princeton University from 2010 to the fall of 2011. He worked as an assistant professor at International Center for Quantum Materials (ICQM) at Peking University from the fall of 2011 to the summer of 2018. He is currently an associate researcher at Institute of Semiconductors, CAS. His research interests focus on the quantum transport of two-dimensional electron (and hole) gas, topological matters (topological insulators and Weyl fermions), and the non-equilibrium states under microwave (radio-frequency).



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