Monolayer behaviour in bulk ReS2 due to electronic and vibrational decoupling.
Semiconducting transition metal dichalcogenides consist of monolayers held together by weak forces where the layers are electronically and vibrationally coupled. Isolated monolayers show changes in electronic structure and lattice vibration energies, including a transition from indirect to direct bandgap. Here we present a new member of the family, rhenium disulphide (ReS2), where such variation is absent and bulk behaves as electronically and vibrationally decoupled monolayers stacked together. From bulk to monolayers, ReS2 remains direct bandgap and its Raman spectrum shows no dependence on the number of layers. Interlayer decoupling is further demonstrated by the insensitivity of the optical absorption and Raman spectrum to interlayer distance modulated by hydrostatic pressure. Theoretical calculations attribute the decoupling to Peierls distortion of the 1T structure of ReS2, which prevents ordered stacking and minimizes the interlayer overlap of wavefunctions. Such vanishing interlayer coupling enables probing of two-dimensional-like systems without the need for monolayers.
1] State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China [2] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Sefaattin
S
Tongay
Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerpen B-2020, Belgium.
Hasan
H
Sahin
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Changhyun
C
Ko
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Alex
A
Luce
1] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [2] Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Anhui 230027, China.
Wen
W
Fan
Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Kai
K
Liu
1] State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China [2] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
Jian
J
Zhou
Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Ying-Sheng
YS
Huang
Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
Ching-Hwa
CH
Ho
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Jinyuan
J
Yan
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
D Frank
DF
Ogletree
Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Shaul
S
Aloni
Department of Thermal Science and Energy Engineering, University of Science and Technology of China, Anhui 230027, China.
Jie
J
Ji
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China.
Shushen
S
Li
State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China.
Jingbo
J
Li
Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerpen B-2020, Belgium.
F M
FM
Peeters
1] State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China [2] Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA [3] Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Junqiao
J
Wu