The excitonic insulator (EI) phase, arising from the spontaneous formation of electron-hole bound states in semimetals or small gap semiconductors, has been predicted for decades but its experimental observation remains elusive. In this talk, we report systematic studies of WTe2 monolayer insulator and uncover evidence supporting this monolayer crystal as an EI. Our experiments on high-quality transport devices reveal the presence of an intrinsic insulating state at the charge neutrality point (CNP) in clean samples. The state exhibits both a strong sensitivity to the electric displacement field and a Hall anomaly that are consistent with the excitonic pairing. We confirm the correlated nature of the charge-neutral insulator by tunneling spectroscopy. The results support the existence of an EI phase in the clean limit and rule out alternative scenarios of a band insulator or a localized insulator. These observations lay the foundation for understanding a new class of correlated insulators with nontrivial topology and identify monolayer WTe2 as a promising candidate for exploring quantum phases of ground-state excitons.
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Presenters
Yanyu Jia
Princeton University
Department of Physics, Princeton University
Authors
Yanyu Jia
Princeton University
Department of Physics, Princeton University
Pengjie Wang
Princeton University
Department of Physics, Princeton University
Cheng Li Chiu
Princeton University
Zhida Song
Princeton University
Guo Yu
Princeton University
Department of Physics, Princeton University
Berthold Jaeck
Princeton University
Physics, Hong Kong University of Science and Technology
Shiming Lei
Princeton University
Rice Univ
Sebastian Klemenz
Princeton University
F Alexandre Cevallos
Princeton University
Michael Onyszczak
Department of Physics, Princeton University
Princeton University
Nadezhda Fishchenko
Princeton University
Xiaomeng Liu
Princeton University
Gelareh Farahi
Princeton University
Fang Xie
Princeton University
Physics, Princeton University
Yuanfeng Xu
Max Planck Institute of Microstructure Physics
Max Planck Institute, Halle, Germany
Physics, Max Planck Institute of Microstructure
Max Planck Inst Microstructure
Kenji Watanabe
National Institute for Materials Science
National Institute for Materials Science, Japan
National Institure for Materials Science
Advanced Materials Laboratory, National Institute for Materials Science
NIMS
National Institute of Materials Science
National Institute for Materials Science (NIMS)
Research Center for Functional Materials, National Institute for Materials Science
National Institute for Materials Science,1-1 Namiki
National Institute of Material Science
National Institute for Materials Science, Tsukuba, Japan
Research Center for Functional Materials, NIMS
National Institute of Materials Science, Tsukuba, Japan
National Institude for Materials Science
National Institute for Materials Science, Tsukuba, Ibaraki, Japan
Research Center for Functional Materials, National Institute for Materials Science, Tsukuba 305-0044, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials
NIMS - Japan
National Institute for Materials Science ,Japan
National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
National Institute for Material Science
National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science Japan
NIMS Tsukuba
National Institute for Materials Science, Research Center for Functional Materials, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
National Institue for Material Science
National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
Materials, NIMS
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
Research Center for Functional Materials, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials Science
International Center for Materials nanoarchtectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
NIMS Suguba
NIMS, Tsukuba, Japan
National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
National institute of material science
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
Advanced Materials Laboratory, NIMS
Research Center for Functional Materials, National Institute for Materials Science, Ibaraki, Japan
National Institute for Materials Science, Research Center for Functional Materials
National Institute of Material Science, Japan
Tsukuba, National Institute for Materials Science
Takashi Taniguchi
National Institute for Materials Science
National Institute for Materials Science, Japan
National Institure for Materials Science
Advanced Materials Laboratory, National Institute for Materials Science
NIMS
National Institute of Materials Science
National Institute for Materials Science (NIMS)
International Center for Materials Nanoarchitectonics, National Institute for Materials Science
National Institute for Materials Science,1-1 Namiki
National Institute of Material Science
National Institute for Materials Science, Tsukuba, Japan
International Center for Materials Nanoarchitectonics, NIMS
Research Center for Functional Materials, National Institute for Materials Science
National Institute of Materials Science, Tsukuba, Japan
National Institude for Materials Science
International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba 305-0044, Japan
International Center for Materials Nanoarchitectonics, National Institute for Materials
NIMS - Japan
National Institute for Materials Science ,Japan
National Institute for Materials Science, Tsukuba, 305-0044, Ibaraki, Japan
National Institute for Material Science
National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
National Institute for Material Science Japan
8International Center for Materials Nanoarchitectonics
NIMS Tsukuba
National Institute for Materials Science: Namiki, Tsukuba, Ibaraki, JP
National Institue for Material Science
National Institute for Materials Science,1-1 Namiki, Tsukuba, 305-0044, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan, Research Center for Functional Materials, National In
Research Center for Functional Materials, Japan
Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
International Center for Material Nanoarchitectonics, National Institute for Materials Science
International Center for Materials Nanoarchitectonics
NIMS Suguba
NIMS, Tsukuba, Japan
National Cheng Kung University
National Institute for Materials Science, Namiki 1-1, Tsukuba, 305-0044, Ibaraki, Japan
National institute of material science
Advanced Materials Laboratory, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
Advanced Materials Laboratory, NIMS
National Institute for Materials Science, International Center for Materials Nanoarchitectonics
National Institute of Material Science, Japan
Tsukuba, National Institute for Materials Science
Andrei B Bernevig
Department of Physics, Princeton University
Princeton University
Princeto University, Princeton, USA
Physics, Princeton University
Robert Cava
Princeton University
Department of Chemistry, Princeton University
Leslie M Schoop
Princeton University
Princeto University, Princeton, USA
Department of Chemistry, Princeton University
Ali Yazdani
Princeton University
Joseph Henry Laboratories & Department of Physics, Princeton University
