title: Bidirectional negative differential thermal resistance in three-segment Frenkel-Kontorova lattices.
abstract: By coupling three nonlinear 1D lattice segments, we demonstrate a thermal insulator model, where the system acts like an insulator for large temperature bias and a conductor for very small temperature bias. We numerically investigate the parameter range of the thermal insulator and find that the nonlinear response (the role of on-site potential), the weakly coupling interaction between each segment, and the small system size collectively contribute to the appearance of bidirectional negative differential thermal resistance (BNDTR). The corresponding exhibition of BNDTR can be explained in terms of effective phonon-band shifts. Our results can provide a new perspective for understanding the microscopic mechanism of negative differential thermal resistance and also would be conducive to further developments in designing and fabricating thermal devices and functional materials.
authors.affiliation: Guangdong Provincial Key Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou 510006, People's Republic of China.
authors.forename: Ya-Li
authors.initials: YL
authors.lastname: Ou
authors.forename: Shi-Cai
authors.initials: SC
authors.lastname: Lu
authors.forename: Cai-Tian
authors.initials: CT
authors.lastname: Hu
authors.forename: Bao-Quan
authors.initials: BQ
authors.lastname: Ai