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Gate and Temperature Driven Phase Transitions in Few-Layer MoTe2.
Hugo Kowalczyk1, Johan Biscaras1, Nashra Pistawala2
1Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, 75005 Paris, France.
ACS Nano
|March 27, 2023
Summary
Electrostatic fields do not induce the 2H-1T' structural transition in molybdenum ditelluride (MoTe2). High ion mobility in few-layer tellurides facilitates structural changes through other means, not pure gating.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Nanotechnology
Background:
- Molybdenum ditelluride (MoTe2) exists in semiconducting (2H) and semimetallic (1T', Td) phases with distinct electronic transport properties.
- Structural transitions between these phases, particularly 2H to 1T', are of interest for device applications and potential topological properties.
- Previous claims suggested electrostatic gating could induce the 2H-1T' transition in MoTe2.
Purpose of the Study:
- To investigate the possibility of inducing a 2H-1T' structural transition in few-layer MoTe2 using electrostatic gating.
- To understand the role of ion mobility and external parameters in structural phase transitions of few-layer tellurides.
- To clarify the mechanism behind structural changes in MoTe2 for potential device applications.
Main Methods:
- Extensive Raman spectroscopy measurements were performed.
- Experiments varied layer thickness, temperature, and electrostatic doping.
- Measurements were conducted on few-layer 2H-MoTe2, 1T'-MoTe2, and Td-WTe2.
Main Results:
- Few-layer tellurides exhibit high ion mobility, influenced by electric fields and temperature.
- These conditions can lead to tellurium (Te) cluster formation and vacancies, facilitating structural transitions.
- The study found no evidence that a pure electrostatic field can induce the 2H-1T' transition in MoTe2.
Conclusions:
- The purported 2H-1T' transition in MoTe2 is not achievable through electrostatic gating alone.
- Structural transitions in few-layer tellurides are primarily driven by ion mobility effects under varying external conditions.
- These findings impact the understanding and potential application of MoTe2 in electronic devices.
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