Johannes Lischner (Imperial College, London)

Controlling the electronic structure of 2d materials by twisting and defects

Thursday, 13 February 2020, 3pm (MBP1 026)



Peizhe Tang (MPI for the Structure and Dynamics of Matter, Hamburg)

Phase transitions and electronic tuning in magnetic topological materials

Tuesday, 18 February 2020, 11am (26C 401)

The interplay between magnetism and topology brings rich physics in the condensed matter physics in recent years. Many exotic phenomena have been observed in related systems, including the quantum anomalous Hall (QAH) effect, Weyl fermions, and antiferromagnetic (AFM) Dirac fermions. In this seminar, I will talk about three topics. The first one is about the magnetic phase transition driven by topological phase transition in magnetically doped topological insulator thin films, such as Cr doped Bi2(SexTe1-x)3 thin films [1]. In the second part, I will expand the notion of Dirac fermions into AFM system, in which both time reversal symmetry (T) and inversion symmetry (P) are broken but their combination PT is survived [2]. The third one is about the QAH phase with large Chern number driven by electric field in MnBi2Te4 thin film, whose 3D bulk state is reported as an AFM TI and thick film as axion insulator [3]. Our results provide several possible platforms to study the interplay of topological physics and magnetisms.

[1] Jingsong Zhang, Cuizu Chang, Peizhe Tang, et.al., Science 339, 1582 (2013)
[2] Peizhe Tang, Quan Zhou, Gang Xu, Shou-Cheng Zhang, Nature Physics 12, 1100 (2016)
[3] Shiqiao Du, et.al., arXiv:1909.01194 (2019)