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Xu S, Evans-Lutterodt K, Li S, Williams NL, Hou B, Huang JJ, Boebinger MG, Lee S, Wang M, Singer A, Guo P, Qiu DY, Cha JJ. Lithiation Induced Phases in 1T'-MoTe 2 Nanoflakes. ACS NANO 2024. [PMID: 38889099 DOI: 10.1021/acsnano.4c06330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
Multiple polytypes of MoTe2 with distinct structures and intriguing electronic properties can be accessed by various physical and chemical approaches. Here, we report electrochemical lithium (Li) intercalation into 1T'-MoTe2 nanoflakes, leading to the discovery of two previously unreported lithiated phases. Distinguished by their structural differences from the pristine 1T' phase, these distinct phases were characterized using in situ polarization Raman spectroscopy and in situ single-crystal X-ray diffraction. The lithiated phases exhibit increasing resistivity with decreasing temperature, and their carrier densities are two to 4 orders of magnitude smaller than the metallic 1T' phase, as probed through in situ Hall measurements. The discovery of these gapped phases in initially metallic 1T'-MoTe2 underscores electrochemical intercalation as a potent tool for tuning the phase stability and electron density in two-dimensional (2D) materials.
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Affiliation(s)
- Shiyu Xu
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
| | - Kenneth Evans-Lutterodt
- National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Shunran Li
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
- Energy Sciences Institute, Yale West Campus, West Haven, Connecticut 06516, United States
| | - Natalie L Williams
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York 14853, United States
| | - Bowen Hou
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
| | - Jason J Huang
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Matthew G Boebinger
- Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee 37830 United States
| | - Sihun Lee
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Mengjing Wang
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Andrej Singer
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Peijun Guo
- Department of Chemical and Environmental Engineering, Yale University, New Haven, Connecticut 06511, United States
- Energy Sciences Institute, Yale West Campus, West Haven, Connecticut 06516, United States
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06511, United States
| | - Judy J Cha
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, United States
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Cui X, Yan H, Yan X, Zhou K, Cai Y. Promoted Electronic Coupling of Acoustic Phonon Modes in Doped Semimetallic MoTe 2. ACS NANO 2023; 17:16530-16538. [PMID: 37646299 DOI: 10.1021/acsnano.3c01229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
As a prototype of the Weyl superconductor, layered molybdenum ditelluride (MoTe2) encompasses two semimetallic phases (1T' and Td) which differentiate from each other via a slight tilting of the out-of-plane lattice. Both phases are subjected to serious phase mixing, which complicates the analysis of its origin of superconductivity. Herein, we explore the electron-phonon coupling (EPC) of the monolayer semimetallic MoTe2, without phase ambiguity under this thickness limit. Apart from the hardening or softening of the phonon modes, the strength of the EPC can be strongly modulated by doping. Specifically, longitudinal and out-of-plane acoustic modes are significantly activated for electron doped MoTe2. This is ascribed to the presence of rich valley states and equispaced nesting bands, which are dynamically populated under charge doping. Through comparing the monolayer and bilayer MoTe2, the strength of EPC is found to be less likely to depend on thickness for neutral samples but clearly promoted for thinner samples with electron doping, while for hole doping, the strength alters more significantly with the thickness than doping. Our work explains the issue of the doping sensitivity of the superconductivity in semimetallic MoTe2 and establishes the critical role of activating acoustic phonons in such low-dimensional materials.
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Affiliation(s)
- Xiangyue Cui
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, 999078, China
| | - Hejin Yan
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, 999078, China
| | - Xuefei Yan
- School of Microelectronics Science and Technology, Sun Yat-Sen University, Zhuhai 519082, China
- Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems, Sun Yat-Sen University, Zhuhai 519082, China
| | - Kun Zhou
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798 Singapore
- Environmental Process Modelling Centre, Nanyang Environment and Water Research Institute, Nanyang Technological University, 1 Cleantech Loop, 637141 Singapore
| | - Yongqing Cai
- Joint Key Laboratory of the Ministry of Education, Institute of Applied Physics and Materials Engineering, University of Macau, Taipa, Macau, 999078, China
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Wang M, Kumar A, Dong H, Woods JM, Pondick JV, Xu S, Hynek DJ, Guo P, Qiu DY, Cha JJ. A Gapped Phase in Semimetallic T d -WTe 2 Induced by Lithium Intercalation. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2200861. [PMID: 35488783 DOI: 10.1002/adma.202200861] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/20/2022] [Indexed: 06/14/2023]
Abstract
The Weyl semimetal WTe2 has shown several correlated electronic behaviors, such as the quantum spin Hall effect, superconductivity, ferroelectricity, and a possible exciton insulator state, all of which can be tuned by various physical and chemical approaches. Here, a new electronic phase in WTe2 induced by lithium intercalation is discovered. The new phase exhibits an increasing resistivity with decreasing temperature and its carrier density is almost two orders of magnitude lower than the carrier density of the semimetallic Td phase, probed by in situ Hall measurements as a function of lithium intercalation. The theoretical calculations predict the new lithiated phase to be a potential charge density wave (CDW) phase with a bandgap of ≈0.14 eV, in good agreement with the in situ transport data. The new phase is structurally distinct from the initial Td phase, characterized by polarization-angle-dependent Raman spectroscopy, and large lattice distortions close to 6% are predicted in the new phase. This finding of a new gapped phase in a 2D semimetal demonstrates electrochemical intercalation as a powerful tuning knob for modulating electron density and phase stability in 2D materials.
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Affiliation(s)
- Mengjing Wang
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Aakash Kumar
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Hao Dong
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06511, USA
| | - John M Woods
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Joshua V Pondick
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Shiyu Xu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - David J Hynek
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Peijun Guo
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
- Department of Chemical and Environmental Engineering, Yale University, New Haven, CT, 06511, USA
| | - Diana Y Qiu
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
| | - Judy J Cha
- Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT, 06511, USA
- Energy Sciences Institute, Yale West Campus, West Haven, CT, 06516, USA
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