Evidences for the exciton gas phase and its condensation in monolayer 1T-ZrTe2

ORAL

Abstract

Here we report a distinct correlated phase beyond the 2×2 CDW ground state emerging in epitaxially grown monolayer 1T-ZrTe2 and its investigation by angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling microscopy (STM). The results show novel band- and energy-dependent folding behavior in a two-step process, evidenced by an exciton gas phase prior to its condensation into the final CDW state. The excellent agreement between experiments and theoretical predictions on the recovery of the pristine band structure by carrier-density-dependent suppression of the CDW state further corroborates the monolayer 1T-ZrTe2 as an EI. Our findings provide a versatile two-dimensional platform that allows tuning of the excitonic effect.

*Research performed at ALS (thin film growth and ARPES) is supported by the Office of Basic Energy Sciences, US DOE under Contract No. DE-AC02-05CH11231. The work at Stanford University and SLAC National Accelerator Laboratory (thin film characterization, theory calculations) was supported by the Office of Basic Energy Sciences, US DOE under Contract No. DE-AC02-76SF00515. Part of this research used Beam line 03U of the Shanghai Synchrotron Radiation Facility, which is supported by ME2 project under Contract No. 11227902 from National NSF of China. A portion of the computational work was performed using the resources of the National Energy Research Scientific Computing Center (NERSC) supported by the U.S. Department of Energy, Office of Science, under Contract No. DE-AC02-05CH11231. S. T. acknowledges the financial support from the National Natural Science Foundation of China (No. 11704395, No. 11974370), ‘Strategic Priority Research Program (B)’ of the Chinese Academy of Sciences (No. XDB04010600). D. S. acknowledges the support by National Natural Science Foundation of China (Grant No. U2032208). J. H. and C. H. acknowledge support from the NRF grant funded by the Korean government (MSIT) (No. 2020K1A3A7A09080369 and 2021R1A2C1004266).

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Publication: https://arxiv.org/pdf/2201.11592.pdf

Presenters

  • Chunjing Jia

    • University of Florida

Authors

  • Chunjing Jia

    • University of Florida

  • Thomas Devereaux

    • Stanford Univ
    • Stanford University

  • Jonathan A Sobota

    • Stanford University

  • Patrick S Kirchmann

    • SLAC - Natl Accelerator Lab

  • Sung-Kwan Mo

    • Lawrence Berkeley National Laboratory

  • Zhixun Shen

    • Stanford University
    • Stanford Insitute for Materials and Energy Sciences
    • Stanford

  • Shujie Tang

    • Chinese Academy of Science