Nodal line topological superconducting state in quasi-one-dimensional A2Cr3As3 (A = K, Rb, Cs) superconductors
M. Wang+, W. LiMing+, T. Zhou+* 1)
+Guangdong Basic Research Center of Excellence for Structure and Fundamental Interactions of Matter,
Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials,
School of Physics, South China Normal University, 510006 Guangzhou, China
*Guangdong-Hong Kong Joint Laboratory of Quantum Matter, Frontier Research Institute for Physics,
South China Normal University, 510006 Guangzhou, China
Abstract
In this theoretical study, we examine the topological properties of the
recently discovered A2Cr3As3 (A = K, Rb, Cs) superconductors. In
the superconducting state, characterized by a typical pz-wave pairing
symmetry, a line nodal exists in the kz=0 plane, confirming the system
as a topological nodal-line superconductor. When considering an open
boundary along the z-direction, flat surface bands emerge. In contrast,
when an s-wave pairing symmetry is considered, the system becomes fully
gapped and topologically trivial. Additionally, we investigate the
spectral function and the local density of states, which may be employed
to experimentally detect the topological features.