题目：How to design topological superconductivity from accurate band structure calculations

报告人：徐刚

时间：2025年11月7日（周五）下午15:30

地点：紫金港校区海纳苑8幢215报告厅

摘要：

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 are 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 accurate band structure calculations.

个人简介：

徐刚，华中科技大学教授，博士生导师，国家脉冲强磁场科学中心副主任，荣获中国科学院杰出成就奖（集体）、中国青年五四奖章（集体）等荣誉。开发了一套拓扑量子物态计算程序，取得了多项极具国际影响力的原创成果：发现了HgCr2Se4、EuCd2As2等优质磁性拓扑材料被实验实现；提出了拓扑超导设计新方案，预言了Fe（Se,Te）中的拓扑超导和马约拉纳零能模被实验证实；发现了多个笼目材料的量子物性被实验观测；发展了多极矩序参量高效计算方法并预言了RuI3中的八极矩基态。发表SCI论文90多篇，其中Nature及其子刊、PRL等顶级期刊论文28篇，总引用1.48万多次，27篇论文单引超过100次。主持科技部重点研发计划项目2项、基金委面上项目2项。作为核心骨干，负责“十四五”重大科技基础设施《脉冲强磁场实验装置优化提升》项目建设意义等内容编写，成功获批，总投资约21亿元。