Disorder is ubiquitous in condensed matter systems. The interplay of disorder and topology gives rise to important phases such as quantum Hall effect and topological Anderson insulators. In this talk, I will first focus on an important type of disorder, i.e., the random flux. We show that random flux is able to drive quantum phase transition from metals to higher-order topological insulators in the Benalcazar-Bernevig-Hughes model [1,2]. I will then show the anisotropic phase transition sequence between weak and strong topological phases in Chern insulators induced by random flux and the consequent new quantum criticality that lies outside quantum Hall universality [3]. Finally, I will discuss how will disorder induce a Kosterlitz-Thouless (KT) type topological phase transitions in altermagnetism, a recently discovered new magnetic phase [4,5].

References:

1. C. A. Li et al., Physical Review Letters 125 166801 (2020);

2. C. A. Li et al., Physical Review B 106, L081410 (2022);

3. C. A. Li et al., Physical Review B 111, 214207 (2025);

4. C. A. Li et al., Physical Review Letters 136 066303 (2026).

5. C. A. Li, arXiv:2605.23607 (2026).

李长安博士,合肥国家实验室研究员, 中科大博士生导师，入选国家级海外高层次人才。于2014年获得北京师范大学学士学位，2019年获得香港大学物理学博士学位。2019年西湖大学做博士后，2020年至2025年在德国维尔茨堡大学从事博士后研究，2026年全职回国。他的研究兴趣主要集中在量子物质的拓扑相、量子输运与调控、无序效应和非厄米物理等方面。目前已发表第一作者/通讯作者论文20余篇，其中多个工作被PRL选为编辑推荐和封面文章，部分理论预言得到实验证实。