Persistent Charge-Density-Wave Order in Single-Layer TaSe2

Hyejin Ryu; Yi Chen; Heejung Kim; Hsin-Zon Tsai; Shujie Tang; Juan Jiang; Franklin Liou; Salman Kahn; Caihong Jia; Arash A Omrani; Ji Hoon Shim; Zahid Hussain; Zhi-Xun Shen; Kyoo Kim; Byung Il Min; Choongyu Hwang; Michael F Crommie; Sung-Kwan Mo

doi:10.1021/acs.nanolett.7b03264

Persistent Charge-Density-Wave Order in Single-Layer TaSe₂

Nano Lett. 2018 Feb 14;18(2):689-694. doi: 10.1021/acs.nanolett.7b03264. Epub 2018 Jan 9.

Authors

Hyejin Ryu^{1

2}, Yi Chen³, Heejung Kim⁴, Hsin-Zon Tsai³, Shujie Tang^{1

5}, Juan Jiang¹, Franklin Liou³, Salman Kahn³, Caihong Jia^{3

6}, Arash A Omrani³, Ji Hoon Shim^{4

7}, Zahid Hussain¹, Zhi-Xun Shen^{5

8}, Kyoo Kim^{2

4}, Byung Il Min⁴, Choongyu Hwang⁹, Michael F Crommie^{3

10

11}, Sung-Kwan Mo¹

Affiliations

¹ Advanced Light Source, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
² Max Planck POSTECH Center for Complex Phase Materials, Pohang University of Science and Technology , Pohang 37673, Korea.
³ Department of Physics, University of California , Berkeley, California 94720, United States.
⁴ Department of Physics, Pohang University of Science and Technology , Pohang 37673, Korea.
⁵ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory , Menlo Park, California 94025, United States.
⁶ Henan Key Laboratory of Photovoltaic Materials and Laboratory of Low-dimensional Materials Science, Henan University , Kaifeng 475004, People's Republic of China.
⁷ Department of Chemistry and Division of Advanced Nuclear Engineering, Pohang University of Science and Technology , Pohang 37673, Korea.
⁸ Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University , Stanford, California 94305, United States.
⁹ Department of Physics, Pusan National University , Busan 46241, Korea.
¹⁰ Materials Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.
¹¹ Kavli Energy Nano Sciences Institute at the University of California Berkeley and the Lawrence Berkeley National Laboratory , Berkeley, California 94720, United States.

PMID: 29300484
DOI: 10.1021/acs.nanolett.7b03264

Abstract

We present the electronic characterization of single-layer 1H-TaSe₂ grown by molecular beam epitaxy using a combined angle-resolved photoemission spectroscopy, scanning tunneling microscopy/spectroscopy, and density functional theory calculations. We demonstrate that 3 × 3 charge-density-wave (CDW) order persists despite distinct changes in the low energy electronic structure highlighted by the reduction in the number of bands crossing the Fermi energy and the corresponding modification of Fermi surface topology. Enhanced spin-orbit coupling and lattice distortion in the single-layer play a crucial role in the formation of CDW order. Our findings provide a deeper understanding of the nature of CDW order in the two-dimensional limit.

Keywords: 2D materials; ARPES; CDW; MBE; STM; TaSe2; Transition metal dichalcogenides; charge density wave.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.
Research Support, Non-U.S. Gov't