Janus monolayer of WSeTe, a new structural phase transition material driven by electrostatic gating

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Phase transition materials are crucial for electronic devices like sensors and memory.
• Controlling structural phase transitions in low-dimensional materials dynamically is challenging.
• Previous work demonstrated semiconductor-semimetal transitions in monolayer MoTe2 via electrostatic gating.

Purpose of the Study:

• To screen Janus transition metal dichalcogenides (MXY) for novel two-dimensional (2D) phase transition materials.
• To investigate the dynamic control of structural phase transitions in these 2D materials using electrostatic gating.

Main Methods:

• Density functional theory (DFT) calculations were employed for screening.
• Screening focused on the Janus family of transition metal dichalcogenides (MXY).
• Investigated the energy differences between H and T' phases and kinetic barriers for phase transitions.

Main Results:

• The Janus monolayer of WSeTe exhibits reversible phase transitions modulated by electrostatic gating.
• A small energy difference (48 meV) between H and T' phases facilitates the transition.
• A gate voltage of 2.0 V triggers the semiconductor-semimetal transition in WSeTe.
• The kinetic barrier for phase transitions in WSeTe is significantly lower (0.66 eV) than in MoTe2.

Conclusions:

• Janus WSeTe is a promising 2D material for phase transition applications.
• The lower kinetic barrier in WSeTe leads to a three-orders-of-magnitude increase in transition rate.
• This material enables much more rapid response times in electronic devices compared to MoTe2.