title: Thermoelectricity in molecular junctions with harmonic and anharmonic modes.
abstract: We study charge and energy transfer in two-site molecular electronic junctions in which electron transport is assisted by a vibrational mode. To understand the role of mode harmonicity/anharmonicity in transport behavior, we consider two limiting situations: (i) the mode is assumed harmonic, (ii) we truncate the mode spectrum to include only two levels, to represent an anharmonic mode. Based on the cumulant generating functions of the models, we analyze the linear-response and nonlinear performance of these junctions and demonstrate that while the electrical and thermal conductances are sensitive to whether the mode is harmonic/anharmonic, the Seebeck coefficient, the thermoelectric figure-of-merit, and the thermoelectric efficiency beyond linear response, conceal this information.
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario, M5S 3H6, Canada.
authors.forename: Bijay Kumar
authors.initials: BK
authors.lastname: Agarwalla
authors.affiliation: Department of Physics, Soochow University, 1 Shizi Street, Suzhou 215006, China.
authors.forename: Jian-Hua
authors.initials: JH
authors.lastname: Jiang
authors.affiliation: Chemical Physics Theory Group, Department of Chemistry, and Centre for Quantum Information and Quantum Control, University of Toronto, 80 Saint George St., Toronto, Ontario, M5S 3H6, Canada.
authors.forename: Dvira
authors.initials: D
authors.lastname: Segal
keywords: counting statistics; efficiency; molecular junctions; quantum transport; thermoelectricity