强磁场下二碲化钨二维纳米材料的电子结构和新型量子行为研究

As a typical layered semimetal with strong spin-orbit coupling , WTe2 is an ideal system to study the confined quantum behaviors. Recently, WTe2 has attracted tremendous attentions for its extremely large magnetoresistace, pressure-driven superconductivity and even "Type II" Weyl point as theories predict. Compared with its bulk counterpart, the quantum behaviors of WTe2 nanosheets (specially the atomic-layer nanostructrue) under high magnetic field have rarely been studied yet. In this project, we attempt to explore the electronic structure and magnetic & electrical properties as well as the exotic quantum behaviors of WTe2 nanosheet under high magnetic field. The layer number dependent quantum oscillations and the derived electronic structure and magnetoresistance variation of WTe2 nanosheet will be firstly studied. Then, the atomic thickness WTe2 nanosheet will be used to study the Ising pairing superconducting, Weyl semimetal and the anisotropic magnetoresistance effect. Our studies will not only provide much insight into the exotic quantum behaviors in WTe2 ultrathin nanosheet, but also shed new light on the nature of the extremely large magnetoresistance effect in bulk WTe2, as well as enrich the structure-function relationship of two-dimensional materials under high magnetic field.

二碲化钨作为强自旋轨道耦合层状半金属，是研究限域量子行为的理想材料。近年来，由于在其单晶块材发现极大磁阻效应、加压诱导超导电性、甚至有理论预言其为一类新型外尔费米子体系，二碲化钨迅速成为材料和凝聚态等领域研究热点。相对于单晶块体，二碲化钨二维纳米材料（特别是原子层厚度限域纳米结构）在强磁场下的电子结构和量子行为研究还非常缺乏。本项目利用强磁场研究二碲化钨二维纳米材料的电子结构和磁电性能，并对可能出现的新奇量子行为进行探索。项目将首先制备和研究系列层数纳米片在强磁场下量子振荡行为，获得其电子结构和磁阻随着厚度的变化规律；其次利用单层纳米片，探索强磁场下可能出现的伊辛配对超导态、外尔半金属态和各向异性磁阻效应等限域量子现象。相关研究不仅能对二碲化钨二维纳米体系新奇量子行为有深入了解，而且为全面理解其块材异常磁阻机制提供重要线索，同时能够对强磁场下二维材料构效关系研究起到推动作用。

项目以层状关联电子材料二碲化钨二维纳米结构为主要研究对象，聚集强磁场下二维纳米材料的电子结构和磁电性能的层数依赖关系，并对可能出现的新型超导态、半金属态及其磁阻效应等进行探索。在本项目实施过程中，项目负责人首先实现了二碲化钨高质量单晶和系列层数可控纳米片制备。进一步拓展调控金属硫属化合物二维固体电子及自旋结构，研究了磁性能和磁场下输运性能耦合，自旋结构和催化性能的联系，实现二维固体Ising超导，半金属态和磁阻效应等新奇限域量子现象。基于以上研究，负责人以第一或者通讯作者发表SCI 论文9 篇（其中Adv. Mater. 2篇，J. Am. Chem. Soc.3篇，Chem 1篇）；申请二维碲化物单晶和超薄纳米片合成专利2项；为RSC Publishing <Smart Materials Series> 丛书撰写关于调控二维磁性相关章节；执行期间申请人入选能源材料化学协同创新中心iChEM Fellow和中科院青促会会员，参与强磁场中心联合获批合肥物质科学技术中心方向项目培育基金一项。