Intrinsic Nernst Effect from Berry Curvature in Superconductors

Area of Science:

• Condensed matter physics
• Solid-state physics
• Superconductivity

Background:

• The Nernst effect in superconductors is conventionally attributed to Cooper pair fluctuations above the critical temperature (Tc) or vortex motion below Tc.
• Existing theories do not fully explain the Nernst effect in clean, vortex-free superconducting states.

Purpose of the Study:

• To investigate the role of Berry curvature in generating an intrinsic Nernst effect in a clean, vortex-free superconducting state.
• To explore the Nernst response in two-dimensional systems with Ising spin-orbit coupling.
• To establish the Nernst effect as a probe of Berry curvature and superconducting pairing symmetry.

Main Methods:

• Theoretical analysis of Berry curvature in Bogoliubov quasiparticles within two-dimensional systems.
• Focus on systems with Ising spin-orbit coupling, relevant to transition-metal dichalcogenides.
• Identification of two distinct superconducting regimes: intervalley s-wave and intravalley chiral p-wave paired states.

Main Results:

• Berry curvature of Bogoliubov quasiparticles intrinsically generates a Nernst response in a clean, vortex-free superconducting state.
• An intervalley s-wave paired state shows a magnetic field-activated Nernst effect.
• An intravalley chiral p-wave paired state exhibits a spontaneous charge or spin Nernst response, even without an external magnetic field.

Conclusions:

• The Nernst effect can arise intrinsically from Berry curvature in superconductors, independent of thermal fluctuations or vortex motion.
• This intrinsic Nernst effect provides a direct method to probe Berry curvature and determine pairing symmetry in two-dimensional spin-orbit-coupled superconductors.
• Proposed experimental setups can circumvent screening issues, enabling detection of this novel Nernst response.