Skyrmion Footprint in the Thermodynamics of the Josephson Superconducting Diode

ABSTRACT We study the thermodynamics of the recently proposed superconducting Josephson junction diode, in particular its specific heat capacity. Its low temperature behavior is determined by the interplay of two intrinsic energy scales of the microscopic Hamiltonian, associated with the superconducting gap and tunneling amplitude of conventional electrons through the junction. If the latter is large enough to overcome the former, the specific heat decays linearly with temperature, reflecting the presence of a current through the diode. In the opposite case, the specific heat decays exponentially and the diode becomes non‐conducting. In the intermediate regime, where both scales are equally large, the specific heat exhibits a non‐trivial power‐law behavior in terms of the temperature. It is demonstrated, that switching on and off of the device is possible by changing the phase of the superconducting condensate only, which is accessible via an external magnetic field. Having magnetic textures hosting magnetic defects, such as skyrmions, antiskyrmions or domain walls as sources of such magnetic field leaves behind unique defect specific footprints in the specific heat.