On January 16, The journal Physical Review Letters published online the title "Chiral Topological Superconductivity inSuperconductor-Obstructed Atomic Insulator-Ferromagnetic Insulator Heterostructures" led by Professor Xu Gang of National High Magnetic Field Center. PhD student Hu Jingnan, undergraduate student Yu Fei from the School of Physics are the co-first authors of the paper, Professor Xu Gang is the corresponding author of the paper, PhD student Luo Aiyun, Lecturer Zou Jinyu, Professor Liu Xin and Post-Doc Pan Xiaohong from the School of Physics jointly completed the relevant work.
Abstract
Implementing topological superconductivity (TSC) and Majorana states (MSs) is one of the most significant and challenging tasks in both fundamental physics and topological quantum computations. In this work, taking the obstructed atomic insulator (OAI) Nb3Br8, s-wave superconductor (SC) NbSe2, and ferromagnetic insulator (FMI) CrI3 as an example, we propose a new setup to realize the 2D chiral TSC and MSs in the SC/OAI/FMI heterostructure, which could avoid the subband problem effectively and has the advantage of huge Rashba spin-orbit coupling. As a result, the TSC phase can be stabilized in a wide region of chemical potential and Zeeman splitting, and four distinct TSC phases with superconducting Chern number N ¼ −1;−2;−3, 3 can be achieved. Moreover, a 2D Bogoliubov–de Gennes Hamiltonian based on the triangular lattice of obstructed Wannier charge centers, combined with the s-wave superconductivity paring and Zeeman splitting, is constructed to understand the whole topological phase diagram analytically. These results expand the application of OAIs and pave a new way to realize the TSC and MSs with unique advantages.
FIG.(a) Schematic of the new chiral TSC setup based on SC/OAI/FMI heterostructure.
FIG.(b) BdG spectrum of Nb3Br8 slab, Wilson loop evolutionand the calculated whole TSC phase diagram of the heterostructure.
Funding
We thank Xi Dai and Biao Lian for helpful discussions. This work is supported by the National Natural Science Foundation of China (12274154).
Link:
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.036601
