受哈工大国际合作处资助，应物理学院陶玲玲教授邀请，莫斯科国立大学Alexander Nikolaev教授将做二维体系中Landau能级的变宽效应报告。欢迎感兴趣的老师和学生积极参加。

报告题目：Magnetic properties of broadened Landau levels at the saddle (or Van Hove) point energy of two dimensional lattices

报告时间：2023年7月18日（星期二），上午10:00-11:00

报告地点：理学楼202

报告摘要：In my report I will discuss when Landau levels, which in weak magnetic fields are usually represented by a discrete energy spectrum, can be broadened in mini-bands, and discuss their properties. Studying the magnetic characteristics of the two dimensional (2D) lattices (hexagonal, graphenelike and the square one) by solving numerically the exact system of discrete equations, which fully describes the broadening of Landau levels, it has been found that the energy spectrum of the Landau level at the energy of the saddle point (which is also known as a Van Hove peak) is principally continuous, so that even in a very small magnetic field this Landau level is always broadened in a miniband. In contrast to that, at other energies in a weak magnetic field the spectrum of Landau levels remains discrete.

报告人简介：Alexander Nikolaev现任莫斯科物理技术学院和莫斯科国立大学教授，长期从事凝聚态物理理论研究。在原子、分子、团簇和低维体系电子结构性质，磁性和超导体系的电子关联效应，以及对称性引起的相变等方面，取得了一系列突破性进展和标志性成果，在国际权威期刊发表学术论文80多篇，是国际上公认的介观物理和纳米电子学专家，其博士后导师Harold Kroto教授是1996年诺贝尔奖得主。此外，Alexander Nikolaev教授在计算程序编写方面具有丰富的经验，是俄罗斯两个广泛使用的计算软件的官方作者之一。