【讲座题目】Topological and Quantum Stability of Low-Dimensional Crystalline Lattices with Multiple Nonequivalent Sublattices
【主 讲 人】Pavel Avramov教授
【讲座时间】2025年11月3日 星期一 下午13:30-15:30
【讲座地点】主楼D座601
【主讲人简介】
韩国庆北国立大学教授，博士生导师。主要从事量子化学、分子动力学、凝聚态物质、电子结构、X射线与光学光谱学、纳米材料（石墨烯及其他二维规则晶格、非周期晶体固体、硅材料、金属纳米团簇）、自旋相关材料、量子材料、低维晶格的拓扑与量子稳定性、陨石材料等研究。
【讲座内容简介】
Topological and quantum stability of several low-dimensional crystalline carbon lattices with multiple non-equivalent sublattices was theoretically analyzed and studied using multilevel simulations. It was shown that symmetrically non-equivalent sublattices may cause uncompensated structural stress with consequent mechanical deformations of low-dimensional crystalline lattices. Assuming that for low-dimensional crystals at least one of the force constant is vanishing, the Topology Conservation Theorem was introduced and proved. It was found that the lack of perfect filling of 2D crystalline space leads to the formation of non-planar lattices with either dramatically elongated lattice translation vectors or completely ruined lattice periodicity. It was shown that for low-dimensional crystals the luck of imaginary modes in phonon dispersion cannot be used as a solid and final proof of the lattice stability. The effect of quantum instability and periodicity breakdown of infinite structural waves was studied using quasiparticle approach. It was shown that either perfect finite-sized, or stabilized structural waves can be synthesized.
