TY - JOUR
T1 - Robust charge-density wave strengthened by electron correlations in monolayer 1T-TaSe2 and 1T-NbSe2
AU - Nakata, Yuki
AU - Sugawara, Katsuaki
AU - Chainani, Ashish
AU - Oka, Hirofumi
AU - Bao, Changhua
AU - Zhou, Shaohua
AU - Chuang, Pei Yu
AU - Cheng, Cheng Maw
AU - Kawakami, Tappei
AU - Saruta, Yasuaki
AU - Fukumura, Tomoteru
AU - Zhou, Shuyun
AU - Takahashi, Takashi
AU - Sato, Takafumi
N1 - Funding Information:
We thank Takumi Sato, T. Taguchi, and C.-W. Chuang for their assistance in the ARPES measurements. We also thank NSRRC-TLS for access to beamline BL21B1. This work was supported by JST-CREST (no. JPMJCR18T1), JST-PRESTO (no. JPMJPR20A8), Grant-in-Aid for Scientific Research on Innovative Areas “Topological Materials Science” (JSPS KAKENHI Grant numbers JP15H05853 and JP15K21717), Grant-in-Aid for Scientific Research (JSPS KAKENHI Grant numbers JP21H04435, JP17H01139), National Natural Science Foundation of China (11725418, 11427903), Ministry of Science and Technology of China (2016YFA0301004, 2015CB921001), Beijing Advanced Innovation Center for Future Chip (ICFC), Tsinghua University Initiative Scientific Research Program, Tohoku-Tsinghua Collaborative Research Fund, Grant for Basic Science Research Projects from the Sumitomo Foundation, Research Foundation of the Electrotechnology of Chubu, Ministry of Science and Technology of the Republic of China, Taiwan, under contract no. MOST 108-2112-M-213-001-MY3, and World Premier International Research Center, Advanced Institute for Materials Research. Y. N. and T. K. acknowledge support from GP-Spin at Tohoku University. A.C. and C.M.C. thank the Ministry of Science and Technology (MOST) of Taiwan, Republic of China, for financially supporting this research under Contract No. MOST 109-2911-I-213-501.
Publisher Copyright:
© 2021, The Author(s).
PY - 2021/12/1
Y1 - 2021/12/1
N2 - Combination of low-dimensionality and electron correlation is vital for exotic quantum phenomena such as the Mott-insulating phase and high-temperature superconductivity. Transition-metal dichalcogenide (TMD) 1T-TaS2 has evoked great interest owing to its unique nonmagnetic Mott-insulator nature coupled with a charge-density-wave (CDW). To functionalize such a complex phase, it is essential to enhance the CDW-Mott transition temperature TCDW-Mott, whereas this was difficult for bulk TMDs with TCDW-Mott < 200 K. Here we report a strong-coupling 2D CDW-Mott phase with a transition temperature onset of ~530 K in monolayer 1T-TaSe2. Furthermore, the electron correlation derived lower Hubbard band survives under external perturbations such as carrier doping and photoexcitation, in contrast to the bulk counterpart. The enhanced Mott-Hubbard and CDW gaps for monolayer TaSe2 compared to NbSe2, originating in the lattice distortion assisted by strengthened correlations and disappearance of interlayer hopping, suggest stabilization of a likely nonmagnetic CDW-Mott insulator phase well above the room temperature. The present result lays the foundation for realizing monolayer CDW-Mott insulator based devices operating at room temperature.
AB - Combination of low-dimensionality and electron correlation is vital for exotic quantum phenomena such as the Mott-insulating phase and high-temperature superconductivity. Transition-metal dichalcogenide (TMD) 1T-TaS2 has evoked great interest owing to its unique nonmagnetic Mott-insulator nature coupled with a charge-density-wave (CDW). To functionalize such a complex phase, it is essential to enhance the CDW-Mott transition temperature TCDW-Mott, whereas this was difficult for bulk TMDs with TCDW-Mott < 200 K. Here we report a strong-coupling 2D CDW-Mott phase with a transition temperature onset of ~530 K in monolayer 1T-TaSe2. Furthermore, the electron correlation derived lower Hubbard band survives under external perturbations such as carrier doping and photoexcitation, in contrast to the bulk counterpart. The enhanced Mott-Hubbard and CDW gaps for monolayer TaSe2 compared to NbSe2, originating in the lattice distortion assisted by strengthened correlations and disappearance of interlayer hopping, suggest stabilization of a likely nonmagnetic CDW-Mott insulator phase well above the room temperature. The present result lays the foundation for realizing monolayer CDW-Mott insulator based devices operating at room temperature.
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U2 - 10.1038/s41467-021-26105-1
DO - 10.1038/s41467-021-26105-1
M3 - Article
C2 - 34620875
AN - SCOPUS:85116523836
SN - 2041-1723
VL - 12
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 5873
ER -