学术沙龙 （5月10日 下午14:30-16:00）

主持人：姚道新 副院长

欢迎广大师生积极参与！

【摘要】

Nowadays, quantum spin liquid (QSL) is actively sought in quantum antiferromagnets with frustrated and/or competing interactions. In experiment, many spin-1/2 antiferromagnetic materials on the frustrated lattices do not show any magnetic order down to very low temperature; spin-liquid-like behaviors have also been observed in the neutron scattering, NMR, and thermal conductance measurements. However, materials inevitably have defects and/or random disorder. For example, in a new triangular spin-liquid-like material YbMgGaO4, the possible mixing of Mg2+ and Ga3+ ions in the material has stimulated further study on the randomness effects. Inspired by the experimental indications, we study the bond randomness in the J1-J2 triangular Heisenberg model, which may be relevant to the randomness effects in the related materials. By using the ED and density matrix renormalization group (DMRG) calculation, we identify a randomness induced disordered (RID) phase that does not show any magnetic order, dimer order, spin glass order, or valence bond glass (VBG) order. The dynamical spin structure factor shows a broad continuum extending to the zero frequency, supporting the gapless excitations obtained from the finite-size gap scaling. We also find the features of entanglement spectrum in the RID phase, which may distinguish the RID phase and the spin liquid phase in the J1-J2 triangular model.

【个人简介】

邬汉青博士于2006年至2010年在beat365中国唯一官方网站物理科学与工程技术学院学习并取得学士学位，2010年至2016年在中国人民大学物理系卢仲毅教授组学习并取得博士学位，2016年至2017年在美国加州州立大学北岭分校D.N.Sheng教授组做博士后研究，2017年12月通过校百人计划加入beat365中国唯一官方网站。邬汉青博士主要从事理论凝聚态物理中强关联电子体系的基础研究，特别是量子多体计算方面。在博士和博士后期间发表Phys. Rev. Lett. 和Phys. Rev. B论文多篇。