通过角分辨光电子能谱揭示LaTe₂体系中的电荷密度波形成

Revealing charge density wave formation in the LaTe2 system by angle resolved photoemission spectroscopy.

作者信息

Garcia D R, Gweon G-H, Zhou S Y, Graf J, Jozwiak C M, Jung M H, Kwon Y S, Lanzara A

机构信息

Department of Physics, University of California, Berkeley, California 94720, USA.

出版信息

Phys Rev Lett. 2007 Apr 20;98(16):166403. doi: 10.1103/PhysRevLett.98.166403. Epub 2007 Apr 18.

DOI:10.1103/PhysRevLett.98.166403

PMID:17501439

Abstract

We present the first direct study of charge density wave (CDW) formation in quasi-2D single layer LaTe2 using high-resolution angle resolved photoemission spectroscopy and low energy electron diffraction. CDW formation is driven by Fermi surface (FS) nesting, however, characterized by a surprisingly smaller gap ( approximately 50 meV) than seen in the double layer RTe2 compounds, extending over the entire FS. This establishes LaTe2 as the first reported semiconducting 2D CDW system where the CDW phase is FS nesting driven. In addition, the layer dependence of this phase in the tellurides and the possible transition from a stripe to a checkerboard phase is discussed.

摘要

我们利用高分辨率角分辨光电子能谱和低能电子衍射，首次对准二维单层LaTe₂中的电荷密度波（CDW）形成进行了直接研究。CDW的形成是由费米面（FS）嵌套驱动的，然而，其特征是与双层RTe₂化合物相比，能隙出奇地小（约50毫电子伏特），且延伸至整个费米面。这使LaTe₂成为首个被报道的二维半导体CDW系统，其中CDW相由费米面嵌套驱动。此外，还讨论了碲化物中该相的层依赖性以及从条纹相到棋盘相的可能转变。