Quantum Interference Enhancement of the Spin-dependent Thermoelectric Response

We investigate the influence of quantum interference and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (S_s), figure-of-merit (Z_sT), and maximum thermodynamic efficiency (η_s^max) caused by destructive quantum interference. Using many-body and single-particle methods, we calculate the response of 1,3-benzenedithiol and cross-conjugated molecule-based junctions subject to an applied magnetic field, finding nearly universal behavior over a broad range of junction parameters withS_s, Z_sT, and η_s^max reaching peak values of 2π/√3 (k/e), 1.51, and 28% of Carnot efficiency, respectively. The influence of off-resonant thermal channels (e.g. phonon heat transport) on the quantum interference-enhanced spin-response is also investigated.