Epitaxial growth and thermal-conductivity limit of singlecrystalline Bi2Se3/In2Se3 superlattices on mica

Thermal transport in superlattices is governed by various phonon-scattering processes. For extracting the phonon-scattering contribution of hetero-interfaces in chalcogenide superlattices, single-crystalline Bi2Se3/In2Se3 （BS/IS） superlattices with minimized defects are prepared on fluorophlogopite mica by molecular beam epitaxy. The cross-plane heat-conducting properties of the BS/IS superlattices are demonstrated to depend precisely on the period thicknesses and constituents of the superlattices, where a minimum in the thermal conductivity indicates a crossover from particle-like to wave-like phonon transport in the superlattices. The thermal-conductivity minimum of the BS/IS superlattices is nearly one order of magnitude lower than that of intrinsic BS film.