Thermal conductivity, diffusivity and specific heat capacity of as-grown, degenerate single-crystalline ZnGa2O4

This work provides the first experimental determination of the low-temperature thermal properties for novel highly pure single-crystalline ZnGa2O4. The temperature dependence of the thermal conductivity, diffusivity and specific heat capacity of as-grown, degenerated ZnGa2O4 single crystals is measured using the 2 omega-method between T = 27 K and room temperature. At room temperature the thermal diffusivity is D approximate to 6.9 center dot 10(-6) m(2)s, the thermal conductivity is lambda approximate to 22.9 W mK(-1) and the specific heat capacity is C (V) approximate to 537 J kgK(-1). The thermal conductivity increases with decreasing temperatures due to reduced phonon-phonon Umklapp scattering down to T = 50 K. For lower temperatures the thermal conductivity is limited by boundary scattering.