Relationship between negative differential thermal resistance and asymmetry segment size

Abstract

Negative differential thermal resistance (NDTR) was investigated in a system consisting of two dissimilar anharmonic lattices exemplified by Frenkel–Kontorova (FK) lattices and Fremi–Pasta–Ulam (FPU) lattices (FK-FPU). The previous theoretical and numerical simulations show the dependence of NDTR are the coupling constant, interface and system size, but we find the segment size also to be an important element. It’s interesting that NDTR region depends on FK segment size rather than FPU segment size in this coupling FK-FPU model. Remarkably, we could observe that NDTR appears in the strong interface coupling strength case which is not NDTR in previous studies. The results are conducive to further developments in designing and fabricating thermal devices.