Laser-Beam-Patterned Topological Insulating States on Thin Semiconducting MoS_{2}.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Two-dimensional topological insulators (TIs) are key for developing low-dissipation spintronic devices.
• Existing 2D TI materials often exhibit fragile edge conduction, limited to specific fabrication conditions.
• Transition metal dichalcogenides are a promising class of 2D TI materials.

Purpose of the Study:

• To achieve controlled patterning of topological insulating phases in molybdenum disulfide.
• To investigate the quantum spin Hall phase in patterned 1T' molybdenum disulfide.
• To explore the potential for voltage-controlled spintronic applications.

Main Methods:

• Controlled laser beam irradiation to pattern the 1T' phase within the 2H phase of molybdenum disulfide.
• Electrical transport measurements to observe quantized resistance.
• Scanning tunneling spectroscopy to probe the bulk band gap.
• Theoretical calculations to support experimental findings.

Main Results:

• Successful fabrication of patterned 1T' molybdenum disulfide phases exhibiting robust topological properties.
• Observation of integer fractions of the quantum of resistance, indicating the quantum spin Hall effect.
• Demonstration of dependence on laser irradiation, magnetic field, and temperature.
• Confirmation of a bulk band gap via scanning tunneling spectroscopy and theoretical analysis.

Conclusions:

• The patterned 1T' molybdenum disulfide phases host a stable quantum spin Hall phase.
• This work provides a viable route for engineering 2D topological states in transition metal dichalcogenides.
• The findings are significant for the advancement of low-power spintronic devices.