Quantum Interference Enhancement of the Spin-Dependent Thermoelectric Response.

Bennett, Runa X; Hendrickson, Joshua R; Bergfield, Justin P · ACS Nano · 2024

basic_science · Level V

Where this comes from

Abstract

We investigate the influence of quantum interference (QI) and broken spin-symmetry on the thermoelectric response of node-possessing junctions, finding a dramatic enhancement of the spin-thermopower (<i>S</i><sub>s</sub>), figure-of-merit (<i>Z</i><sub>s</sub><i>T</i>), and maximum thermodynamic efficiency (η<sub>s</sub><sup>max</sup>) caused by destructive QI. 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 range of junction parameters with <i>S</i><sub>s</sub>, <i>Z</i><sub>s</sub><i>T</i>, and reaching peak values of <math xmlns="http://www.w3.org/1998/Math/MathML"><mn>2</mn><mi>π</mi><mo>/</mo><msqrt><mn>3</mn></msqrt><mrow><mo>(</mo><mi>k</mi><mo>/</mo><mi>e</mi><mo>)</mo></mrow></math>, 1.51, and 28% of Carnot efficiency, respectively. We also find that the quantum-enhanced spin-response is spectrally broad, and the field required to achieve peak efficiency scales with temperature. The influence of off-resonant thermal channels (e.g., phonon heat transport) on this effect is also investigated.