Phase Transition and Superconductivity Enhancement in Se-Substituted MoTe₂ Thin Films

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Few-layer transition metal dichalcogenides (TMDs) MX2 hold promise for topological superconductivity.
• Achieving topological superconductivity requires integrating superconductivity with the quantum spin Hall effect in a single material.

Purpose of the Study:

• To demonstrate a consecutive structural phase transition in Se-substituted MoTe2 thin films.
• To investigate the impact of Se-substitution on the superconductivity of MoTe2.
• To explore the potential for topological superconductivity in this material system.

Main Methods:

• Fabrication of Se-substituted MoTe2 thin films with varying Se concentrations.
• Characterization of structural phase transitions (Td to 1T' to 2H polytypes).
• Measurement and analysis of superconductivity enhancement and two-band superconductivity.

Main Results:

• A consecutive structural phase transition from Td to 1T' to 2H polytype was achieved by increasing Se concentration.
• Se-substitution significantly enhanced the superconductivity of MoTe2 thin films.
• Evidence for the introduction of two-band superconductivity was observed.

Conclusions:

• Chemical constituent control (Se-substitution) provides a novel strategy for phase transitions in MoTe2.
• This approach facilitates the study of s+- superconductivity and potential topological superconductivity.
• The findings pave the way for developing phase-sensitive devices based on MX2 materials.