Title: Two-dimensional Dirac Semimetals Robust Against Spin-orbit Coupling

Speaker: Associate Researcher Yuanjun Jin (South China Normal University, China)

Time: April 2, 10:00 a.m

Venue: Lecture Hall, Room 213, 2nd Floor, Physics Building (Building 18), Guangzhou Wushan Campus

[Abstract]

Graphene is known to host two-dimensional (2D) Dirac fermions. However, due to the small gap introduced by spin-orbit coupling (SOC)，graphene is driven into quantum spin Hall insulator. The realization of stable 2D Dirac points against SOC has attracted much attention because it provides a platform to study the unique transport properties beyond graphene[1]. This talk will discuss the nonsymmorphic symmetry protected 2D Dirac point and its unique properties. When the inversion symmetry is broken, the system possesses non-zero Berry curvature and Berry curvature dipole, leading to the nonlinear Hall effect[2]. Inversion symmetry breaking also makes it possible to realize the coexistence of Dirac and Weyl points and to manipulate the Hall plateaus in unconventional integer quantum Hall effect by strain[3]. Finally, I will also discuss the midgap states induced in the 2D Dirac node line semimetals by in-plane Zeeman field and intrinsic SOC, as well as the midgap states present in a superconductor[4].

Announced by School of Physics and Optoelectronics