Nonreciprocal Current-Induced Zero-Resistance State in Valley-Polarized Superconductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Phenomena

Background:

• Recent experiments revealed a nonreciprocal current-induced zero-resistance state (CIZRS) in twisted trilayer graphene/WSe2 heterostructures.
• This phenomenon, where zero resistance occurs only for specific current directions and magnitudes, presents a significant theoretical challenge.

Purpose of the Study:

• To develop a theoretical framework explaining the observed current-induced zero-resistance state (CIZRS).
• To elucidate the role of electronic structure and current directionality in achieving nonreciprocal superconducting states.

Main Methods:

• Theoretical modeling of twisted trilayer graphene/WSe2 heterostructures.
• Analysis of Fulde-Ferrell (FF) states, valley polarization, and trigonal warping effects.
• Investigation of current-induced domain population and Josephson coupling dynamics.

Main Results:

• The theory identifies threefold degenerate Fulde-Ferrell (FF) states stabilized by valley polarization and trigonal warping.
• A unidirectional current breaks degeneracy, favoring a single FF pairing domain and enabling zero resistance.
• The multidomain nature of the incipient superconducting state explains resistance at low currents or reversed bias due to interdomain coupling mismatch.

Conclusions:

• The proposed theory successfully explains the nonreciprocal current-induced zero-resistance state (CIZRS) in the studied heterostructures.
• The findings highlight the importance of broken symmetry and domain control in realizing exotic superconducting states.
• The study suggests potential realization of triangular finite-momentum states in valley-polarized superconductors.