Nontrivial superconductivity in topological MoTe_2- S crystals

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• Topological Weyl semimetals (TWSs) are crucial for understanding topological phases and topological superconductivity.
• T-phase MoTe2 is a known type-II TWS, but its superconducting properties require further investigation.

Purpose of the Study:

• To investigate the superconductivity and topological characteristics of sulfur-doped T-phase MoTe2.
• To explore the potential of this material as a topological superconductor.

Main Methods:

• Synthesis of sulfur-doped T-phase MoTe2 (MoTe2-xSx, x ~ 0.2).
• Measurements of superconducting properties, including critical temperature (Tc) and superconducting gaps.
• Quasi-particle interference (QPI) pattern analysis and comparison with band-structure calculations.
• Scanning tunneling spectroscopy (STS) to probe surface electronic states.

Main Results:

• Sulfur-doped T-phase MoTe2 exhibits enhanced Tc and displays two-band s-wave bulk superconductivity.
• Evidence of Fermi arc states was observed through QPI measurements and theoretical calculations.
• A significant superconducting gap ( ~ 1.7 meV) was detected on the surface, suggesting topological nontrivial superconductivity.

Conclusions:

• Sulfur-doped T-phase MoTe2 is a promising candidate for topological superconductivity.
• The material serves as a unique platform for studying s-wave superconductivity and the interplay between superconductivity and topological surface states (Fermi arcs).