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Published on: August 2, 2019
Supercurrent modulated by magnetization in a composite topological superconductor junction
1Department of Physics, Southeast University, Nanjing 210096, People's Republic of China.
Summary
Magnetization in a quantum dot junction can induce a supercurrent without a phase gradient. This zero-phase supercurrent, crucial for detecting Majorana fermions, is tunable via magnetization direction and strength.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Materials Science
Background:
- Topological superconductors (TS) exhibit exotic quantum phenomena.
- Understanding supercurrent flow in hybrid structures is key to novel electronics.
- Quantum dots offer tunable platforms for exploring quantum phenomena.
Purpose of the Study:
- To theoretically investigate supercurrent in a composite topological superconductor (TS) junction with a magnetized quantum dot.
- To analyze the influence of magnetization on the current-phase relationship.
- To explore a potential method for detecting Majorana fermions.
Main Methods:
- Tight-binding model.
- Keldysh Green's function method.
- Theoretical analysis of supercurrent in a TS-dot-TS junction.
Main Results:
- Magnetization in the quantum dot significantly modifies the supercurrent-current-phase relationship.
- A nonzero supercurrent flows at zero phase gradient when magnetization has a specific orientation.
- The induced zero-phase supercurrent is controllable by magnetization magnitude and direction.
- Maximum supercurrent occurs at the critical magnetic field for topological phase transition.
Conclusions:
- Magnetization in a quantum dot provides a tunable knob to control supercurrent in TS junctions.
- The induced zero-phase supercurrent offers a promising, experimentally accessible route for Majorana fermion detection.
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