Structural phase transition and electronic structure evolution in Ir_(1-x)Pt_xTe_2 studied by scanning tunneling microscopy  

Pt掺杂IrTe_2中结构相变和电子结构演化的扫描隧道显微学研究（英文）

作　　者：阮威 汤沛哲 房爱芳 蔡鹏 叶存 李昕彤 段文晖 王楠林 王亚愚 

机构地区：[1]State Key Laboratory of Low Dimensional Quantum Physics,Department of Physics, Tsinghua University [2]Institute of Physics, Chinese Academy of Sciences [3]Collaborative Innovation Center of Quantum Matter [4]International Center for Quantum Materials, School of Physics,Peking University

出　　处：《Science Bulletin》2015年第8期798-805,M0004,共9页科学通报（英文版）

基　　金：supported by the National Natural Science Foundation and Ministry of Science and Technology of China(2011CB921901,2011CB921701,2012CB821403,and 2015CB921000)

摘　　要：The IrTe2 transition metal dichalcogenide un- dergoes a series of structural and electronic phase transi- tions when doped with Pt. The nature of each phase and the mechanism of the phase transitions have attracted much attention. In this paper, we report scanning tunneling mi- croscopy and spectroscopy studies of Pt-doped IrTe2 with varied Pt contents. In pure IrTe2, we find that the ground state has a 1/6 superstructure, and the electronic structure is inconsistent with Fermi surface nesting-induced charge density wave order. Upon Pt doping, the crystal structure changes to a 1/5 superstructure and then to a quasi-periodic hexagonal phase. First-principles calculations show that the superstructures and electronic structures are determined by the global chemical strain and local impurity states that can be tuned systematically by Pt doping.当用Pt掺杂并取代过渡金属二硫族化物Ir Te2中的Ir原子时,该体系会发生一系列的结构和电子相变.这些相变的机制引起了广泛关注.本文报道在不同浓度的Pt掺杂的Ir Te2样品上利用扫描隧道显微镜及其谱学手段研究的结果.在没有掺杂的样品中,我们发现体系的基态是一个具有6倍晶胞的条纹状超晶格调制,并且它的电子结构并不支持费米面叠套机制所诱导的电荷密度波序的物理图像.当引入Pt掺杂后,体系的超晶格周期变成了5倍,然后演化为准周期性的六角调制相.第一原理计算表明,体系的超结构和电子结构是由化学压力和局域杂质态决定的,并且它们都受到Pt杂质浓度调制.

关 键 词：IrTe2 Transition metal dichalcogenide Scanning tunneling microscopy Density functionaltheory Charge density wave 

分 类 号：O614.825[理学—无机化学]