THERMAL CONDUCTIVITY MODULATION IN Zr(Hf)SiS MATERIAL SYSTEM BY SUBSTITUTIONAL ATOMS
In solid state materials, heat transport is mainly accomplished by lattice vibration or its collective excitation, phonons. Since thermal conduction is closely related to the properties of crystal lattice, artificially designing the lattice has been proposed to be an effective way to modulate a material's thermal conductivity. In this work, we synthesise a series of ZrSiS, HfZrSiS and HfSiS single crystalline samples by chemical vapor transport. We investigate their intrinsic thermal conductivities along the c-axis using the time-domain thermoreflectance (TDTR) method. The measured thermal conductivities of ZrSiS and HfSiS increase monotonically as temperature decreases from 300 K to 60 K, showing a typical single crystalline feature, while HfZrSiS shows an amorphous or polycrystalline trend. Besides, the general thermal conductivities of Zr(Hf)SiS are higher than most of the quasi-two-dimensional materials. The detailed study of this material system may provide more insights on the thermal transport mechanism in two-dimensional and quasi-two-dimensional materials.