Structural Phase Transition of Multilayer VSe₂

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Vanadium diselenide (VSe2) is a transition metal dichalcogenide (TMD) with potential in electronics and spintronics.
• The 1T-phase of VSe2 exhibits metallic properties.
• Exotic properties like charge/spin density waves and ferromagnetism are observed in VSe2.

Purpose of the Study:

• To investigate the structural and electronic properties of multilayer vanadium diselenide (VSe2).
• To explore the possibility of phase transitions in VSe2 through annealing.
• To understand the thermodynamic stability of different VSe2 phases in two-dimensional (2D) form.

Main Methods:

• Annealing of multilayer VSe2 samples at 650 K.
• Characterization of structural and electronic properties before and after annealing.
• Thermodynamic analysis of 1T and 2H phases in 2D.

Main Results:

• A structural phase transition from the 1T-phase to the 2H-phase of VSe2 was achieved via annealing at 650 K.
• The structural transition was accompanied by a metal-insulator transition.
• The 2H-phase of VSe2 was found to be more thermodynamically stable in 2D compared to the 1T-phase.

Conclusions:

• Annealing is an effective method to control the phase transition and electronic properties of VSe2.
• The 2H-phase of VSe2 is a promising candidate for future electronic and spintronic applications.
• Understanding phase stability is crucial for designing 2D materials.