Nonreciprocal charge transport at topological insulator/superconductor interface

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Topological superconductors are key for topological quantum computation.
• Superconducting proximity effect on topological insulator surface states can induce topological superconductivity.
• Bi₂Te₃/FeTe heterostructures are candidates for realizing such phenomena.

Purpose of the Study:

• To investigate the interaction between superconductivity and topological surface states.
• To detect nonreciprocal transport in Bi₂Te₃/FeTe heterostructures.
• To understand the mechanisms behind the observed nonreciprocity.

Main Methods:

• Investigated nonreciprocal transport (current-direction dependent resistance).
• Studied the Bi₂Te₃/FeTe heterostructure.
• Analyzed the effects of in-plane magnetic fields and angular dependence.

Main Results:

• Observed a largely enhanced nonreciprocal phenomenon associated with the superconducting transition.
• Attributed the low-field nonreciprocal signal to current-induced modulation of supercurrent density via spin-momentum locking.
• Identified evidence for an additional nonreciprocal transport mechanism at high magnetic fields.

Conclusions:

• The Bi₂Te₃/FeTe heterostructure exhibits significant nonreciprocity linked to its topological and superconducting properties.
• Spin-momentum locking plays a role in the observed nonreciprocity under specific conditions.
• Further investigation is needed to fully elucidate the high-field nonreciprocal transport mechanism.