Impact of gap anisotropy of Polar and Anderson-Brinkman-Morel p-wave superconductors on thermoelectric properties of quantum dot hybrids

Abstract We theoretically investigate the thermoelectric transport properties of a hybrid device consisting of a quantum dot (QD) coupled to a ferromagnetic lead and a p-wave, spin-triplet superconducting electrode. We focus on two distinct phases - the Polar and Anderson-Brinkman-Morel (ABM) - both having anisotropic gap structure and pure spin-triplet pairing. To capture the momentum-dependent tunneling between QD and the triplet superconductor (TSC), we introduce a phenomenological angle-dependent weighting of the QD-TSC coupling and analyze two configurations in which the superconducting symmetry axis is parallel or perpendicular to the tunneling axis. Employing the Keldysh Green’s function formalism in the linear response regime, we compute key transport coefficients - electrical and thermal conductance, thermopower, and the thermoelectric figure of merit - based on the anisotropy strength parameter, which is the central focus of this work rather than strong intra-dot correlation physics. Transport coefficients exhibit phase, geometry and anisotropy strength-sensitive behaviors, thereby making them potential probes of superconducting order parameter and nodal orientation. We demonstrate that neglecting anisotropy in modeling conceals important qualitative signatures. Our formulation allows to separately quantify the contribution of triplet Andreev reflection and quasiparticle tunneling and shows that, by mere rotation of the crystallographic axis of the superconductor, it is possible to obstruct or maximize the effective (triplet) Andreev reflection. In the ABM state, the origin of orientation-dependent suppression of Andreev reflection is traced to the azimuthal phase dependence. Moreover, the thermal conductance is enhanced by a few orders of magnitude compared to the conventional s-wave case. The results demonstrate that the anisotropic, orientation-dependent triplet gap strongly governs transport, offering experimentally accessible signatures of the superconducting phase and nodal structure.