How to design topological superconductivity from ab initio calculations

Topological superconductor (TSC) design and Majorana zero mode (MZM) modulation are the most important but challenging task for their great potential in the topological quantum computations. In this talk, I will introduce two new paradigms to realize TSC and MZM, and one 2D TSC calculation program. 1. To overcome the difficulty of heterojunction, we innovatively propose a new scheme to realize TSC and MZM in single material, i.e., superconducting topological metal (SCTM), which host the inverted band structures and superconductivity simultaneously. The TSC properties and MZM in the vortex of the SCTM FeSe_0.5Te_0.5 are calculated for the first time in 2016, which are confirmed by experimental observations in 2018. 2. In order to find more ideal SCTMs, we propose a new strategy by intercalating the superconducting units into the topological insulators as demonstrated in the experimentally synthesizable compounds PdBi₂Te₄ and PdBi₂Te₅. A numerical method to characterize the superconducting spectrum and topological invariants of 2D slab systems using first-principles calculations is also developed in the same work and implemented in the open-source software WannierTools. 3. Based on the obstructed surface states of the obstructed atomic insulator (OAI), we propose a new setup to realize the 2D chiral TSC in NbSe₂-Nb₃Br₈-CrI₃ heterostructure, which could avoid the subband problem effectively. These works pave new way to realize TSC and MZMs in a large class of materials and provide a general tool to design and modulate the TSC system from ab initio calculations.