Thermal superconducting quantum interference proximity transistor

Superconductors are excellent thermal insulators at low temperatures owing to the presence of an energy gap in their density of states(1). Through the so-called proximity effect(2), superconductors can influence the density of states of nearby metallic or superconducting wires. In this way, the local density of states of a wire can be tuned by controlling the phase bias (phi) imposed across it(3). Here we demonstrate a thermal superconducting quantum interference proximity transistor (T-SQUIPT) that enables the phase control of heat currents by exploiting the superconducting proximity effect. Our T-SQUIPT device comprises a quasi-one-dimensional aluminium nanowire forming the weak link embedded in a superconducting rine(4,5) Controlling the phase bias by changing the magnetic flux through the ring shows temperature modulations of up to 16 mK, yielding a temperature-to-flux transfer function that reaches approximately 60 mK Phi(-1)(0). We also demonstrate a hysteretic dependence of the local density of states of T-SQUIPTs on the applied magnetic field due to phase-slip transitions. This allows the T-SQUIPT device to operate as a phase-tunable thermal memory(6)(,7), where the information is encoded in the temperature of the metallic mesoscopic island.

Automated summary

Researchers have demonstrated the phase control of heat currents by utilizing the superconducting proximity effect. They have designed a T-SQUIPT device, which consists of an aluminum nanowire embedded in a superconducting ring. By changing the magnetic flux through the ring, the phase bias can be controlled, leading to temperature modulations. The device also exhibits hysteresis in the local density of states due to phase-slip transitions, allowing it to operate as a phase-tunable thermal memory.