二维晶体电子材料的输运性质与量子相变

项目名称： 二维晶体电子材料的输运性质与量子相变

项目编号： No.11474198

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 刘荧

作者单位： 上海交通大学

项目金额： 90万元

中文摘要： 石墨稀的发现引发了二维晶体电子材料的一个革命性进展。虽然石墨稀具有很好的性能，但存在零带隙等明显的不足。最近发现可以用机械解理方法获得的过渡金属硫族化合物二维晶体材料有较大的带隙，相关的二维电子气体有能带结构，以及超导，磁性和电荷、自旋密度波等有序物态和由于自旋和能谷的耦合导致的新物理现象。本项目将以过渡金属硫族化合物为主要研究对象，在已有的工作基础上全面系统地探讨过渡金属硫化物二维晶体的物理性质，利用上海交大的纳米制备和低温测量条件，研究二维晶体中的能带结构，维度, 界面，及载流子浓度对过渡金属硫化物二维晶体中载流子散射过程的影响，理解制约迁移率的因素，寻找过渡金属硫化物二维晶体中的提高迁移率的途径，探索电荷密度波、超导等不同有序态在二维超导体中的共存与竞争, 半导体－金属，超导体－电荷密度波等量子相变，以及这些新材料的器件应用。

中文关键词： 二维晶体；过度金属硫族化合物；原子尺度晶片；超导；电荷密度波

英文摘要： The discovery of graphene has led to revolutionary advances in two-dimensional (2D) crystalline electronic materials. Even though graphene has some excellent properties, it also has some disadvantages such as a zero energy band gap. Recently discovered atomically thin crystals of transition metal chalcogenides prepared by mechanical exfoliation do have a band gap. The related two dimensional electron gas has a energy band structure, superconductivity, charge and spin density waves, and spin-valley coupling and corresponding novel physics. Building on our previous work and the nanofabrication and low-temperature measurement capabilities at SJTU, we propose to carry out a focused experimental study of atomically thin crystals of transition metal chalcogenides, exploring the effects of band structure, two-dimensionality, interface, and the carrier density on the low-temperature transport processes. We seek to identify factors limiting the mobility of the carriers so as to open pathways for high carrier mobility. We will also study the interplay between superconductivity and density waves, and the quantum phase transitions between semiconductor and metal, as well as that between superconductor and charge density waves. We will also explore possible device applications of these novel electronic materials.

英文关键词： 2D Crystal;Transition Metal Chalcogenide;Atomic scale crystalline flake;Superconductivity;Charge-Density Wave