Nernst Sign-Reversal in the Hexatic Vortex Phase of Weakly Disordered a-MoGe Thin Films

Abstract

The hexatic phase is an intermediate stage in the melting process of a 2D crystal due to topological defects. Recently, this exotic phase was experimentally identified in the vortex lattice of 2D weakly disordered superconducting MoGe by scanning tunneling microscopic measurements. Here we study this vortex state by the Nernst effect, which is an effective and sensitive tool to detect vortex motion, especially in the superconducting fluctuation regime. We find a surprising Nernst sign reversal at the melting transition of the hexatic phase. We propose that they are a consequence of vortex dislocations in the hexatic state which diffuse preferably from the cold to hot.

8 pages, 8 figures

References in corpus (5)

• 2D Melting: From Liquid-Hexatic Coexistence to Continuous Transitions
• Extreme sensitivity of the vortex state in a-MoGe films to radio-frequency electromagnetic perturbation
• Nernst response, viscosity and mobile entropy in vortex liquids
• AC Measurement of the Nernst effect of thin films at low temperatures
• Influence of vortices and phase fluctuations on thermoelectric transport properties of superconductors in a magnetic field

Cited by in corpus (1)

• Evolution of dissipative regimes in atomically thin ${\text{Bi}}_2{\text{Sr}}_2{\text{CaCu}}_2{\text{O}}_{8+x}$ superconductor