Abstract
AbstractThe excitonic insulator (EI) is a Bose-Einstein condensation (BEC) of excitons bound by electron-hole interaction in a solid, which could support high-temperature BEC transition. The material realization of EI has been challenged by the difficulty of distinguishing it from a conventional charge density wave (CDW) state. In the BEC limit, the preformed exciton gas phase is a hallmark to distinguish EI from conventional CDW, yet direct experimental evidence has been lacking. Here we report a distinct correlated phase beyond the 2×2 CDW ground state emerging in 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, which is the signatures of an exciton gas phase prior to its condensation into the final CDW state. Our findings provide a versatile two-dimensional platform that allows tuning of the excitonic effect.
Publisher
Springer Science and Business Media LLC
Subject
General Physics and Astronomy,General Biochemistry, Genetics and Molecular Biology,General Chemistry,Multidisciplinary
Reference43 articles.
1. Mott, N. F. The transition to the metallic state. Philos. Mag. A J. Theor. Exp. Appl. Phys. 6, 287–309 (1961).
2. Jérome, D., Rice, T. M. & Kohn, W. Excitonic Insulator. Phys. Rev. 158, 462–475 (1967).
3. Kohn, W. Excitonic Phases. Phys. Rev. Lett. 19, 439–442 (1967).
4. Eisenstein, J. P. & MacDonald, A. H. Bose-Einstein condensation of excitons in bilayer electron systems. Nature 432, 691–694 (2004).
5. Lozovik, Y. E. & Yudson, V. I. Feasibility of Superfluidity of Paired Spatially Separated Electrons and Holes - New Superconductivity Mechanism. JETP Lett. 22, 274–276 (1975).
Cited by
20 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献