Effect of lattice period on thermal current of Frenkel-Kontorova lattices

Abstract

Effect of lattice period on thermal current of Frenkel-Kontorova (FK) lattices in the underdamped case is investigated by means of numerical calculations. The results indicate that: (i) the negative differential thermal resistance (NDTR) effect completely depends on the period of the FK lattice in the case of fixed amplitude of on-site potential. With the increment of the lattice period, the NDTR effect is gradually disappearing. (ii) For the specific lattice period (a = 0.15), the system’s symmetry greatly affects the NDTR phenomenon. The NDTR effect becomes more and more obvious with the increment of VR. (iii) If the lattice periods of the two segments of coupled FK nonlinear lattices are not equal, the NDTR phenomenon can also occur even though the on-site potential is in symmetry (VL = VR = 1). Meanwhile, with the increment of the average environmental reference temperature, the NDTR gradually disappears. Our results indicate that the lattice period of nonlinear lattices plays a crucial role in the design of thermal devices.