Quantum-enhanced performance of nanoscale thermoelectrics

In a recent paper, we predicted that the linear thermoelectric response of a nanoscale junction is strongly enhanced by quantum interference in the vicinity of a transmission node.\footnote{J.~P.~Bergfield and C.~A.~Stafford, Nano Letters {\bf 9}, 3072 (2009).} In this talk, we use our nonequilibrium many-body transport theory\footnote{J.\ P.\ Bergfield and C.\ A.Stafford, Phys.\ Rev.\ B {\bf 79}, 245125 (2009)} to investigate the performance of thermoelectric devices based on single-molecule junctions, determining the thermodynamic efficiency and power at finite bias. By comparing the linear and nonlinear device characteristics, the applicability of the dimensionless thermoelectric figure-of-merit $ZT$ to predict device performance at the nanoscale is tested. Finally, we report on a class of high-impedance nanoscale devices which possess additional quantum-enhancement, and exhibit high thermodynamic efficiency and $ZT>10$ limited only by the coherence length.