Nonlinear Thermoelectricity with Electron-Hole Symmetric Systems

Area of Science:

• Condensed matter physics
• Quantum electronics
• Solid-state physics

Background:

• Thermoelectric effects typically require broken electron-hole symmetry in the linear regime.
• Nonlinear transport phenomena offer new avenues for thermoelectric applications.

Purpose of the Study:

• To investigate nonlinear thermoelectric effects in tunnel junctions beyond the linear regime.
• To demonstrate absolute negative conductance and thermoelectric power under specific conditions.

Main Methods:

• Theoretical analysis of a tunnel junction between two electrodes.
• Modeling a system with a gapped and a monotonically decreasing density of states.
• Considering a tunnel junction between superconductors with suppressed Josephson contribution.

Main Results:

• Absolute negative conductance and thermoelectric power can be achieved in a thermally biased junction.
• This occurs outside the linear regime, without explicit electron-hole symmetry breaking.
• A prototype system involves a tunnel junction between different superconductors.

Conclusions:

• Nonlinear thermoelectric effects can arise from spontaneous electron-hole symmetry breaking.
• The findings open possibilities for novel thermoelectric devices and applications.
• Characterization of figures of merit for this nonlinear thermoelectric effect is discussed.