报告人：刘丰 教授（宁波大学）

题目：Band structures irrespective topological materials

时间：2025年8月21日（周四）下午16：30

地点：理工楼1226

联系人：贾伟

报告摘要：

Traditional topological insulators often rely on band inversions driven by nonuniform hopping textures and spin-orbit coupling, as exemplified in the Su-Schrieffer-Heeger and Kane-Mele models. In this talk, we present a novel approach utilizing the projective nature of translational symmetry to induce nontrivial topological insulating properties characterized by second-order corner states without band inversion. To substantiate our proposal, we design a photonic crystal with fractional translational symmetry, demonstrating unique directional waveguide edge modes and localized corner modes.

个人简介：

刘丰，1987年11月出生。2006年－2010年在中国人民大学物理学系获学士学位，2015年获日本筑波大学材料物理学博士。曾在日本关西学院大学担任JSPS Fellowship和特任助理教授。2020年4月起加入宁波大学担任特聘教授，并入选浙江省引进计划。目前为东方理工访问学者和绍兴文理学院兼职教授。研究领域为凝聚态理论物理，主要研究方向为拓扑材料理论体系搭建及创新、基于拓扑相的光子晶体材料设计及应用和，提出了零贝尔曲率拓扑态这一新概念和其对应的理论模型二维Su-Schrieffer-Heeger 模型。

代表性论文:

1.F. Liu* , Analytic solution of n-dimensional Su-Schrieffer-Heeger Model, Physical Review B 108, 245140 (2023).

2.F. Liu* and K. Wakabayashi, Higher-order topology and fractional charge in monolayer graphene, Physical Review Research 3,023121 (2021).

3.F. Liu, H.-Y. Deng and K. Wakabayashi, Helical topological edge states in a quadrupole phase, Physical Review Letters 122, 086804 (2019).

4.F. Liu, H.-Y. Deng and K. Wakabayashi, Topological photonic crystals with zero Berry curvature, Physical Review B 97, 035442 (2018).

5.F. Liu* and K. Wakabayashi, Novel topological phase with a zero Berry curvature, Physical Review Letters 118, 076803 (2017).