  Thermal rectification devices can be important for various thermal management
applications. For oscillator chains, thermal rectification was observed when
masses are distributed non-uniformly. Leaning on the importance of topological
materials, we consider here a simple vibrational topological system, the binary
isotope superlattice (BISL). We show that the BISL can be mapped exactly onto
the Su-Schrieffer-Heeger (SSH) model, which has different topological phases,
including topological edge sates. For the case, where there is a single
topological edge state, we show that the BISL exhibits thermal rectification in
the presence of a small nonlinear term. Thermal transport is computed using
temperature reservoirs connected to both extremities. These results have
implications for other classes of topological phonon systems.
