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摘要
In this paper, we study ballistic thermal transport properties at low temperatures in semiconductor nanowires-based heterojunctions under hard-wall boundary conditions (HWBCs) and stress-free boundary conditions (SFBCs). Here, the numerical calculations for the asymmetric heterojunction (ASHJ) and symmetric heterojunction (SHJ) are done. When SFBCs are employed, the transmission coefficient exhibits different behaviors between ASHJ and SHJ especially at low frequency, but when HWBCs are employed, the transmission coefficient displays similar smooth platforms in both heterojunctions. In low temperature limit, the quantized thermal conductance can be observed in SHJ under SFBCs regardless of the structural details. However, this quantization cannot be observed in ASHJ under SFBCs, and the thermal conductance is strongly sensitive to the transverse width ratio rather than the slant angle. With increasing the transverse width ratio, the thermal conductance in both heterojunctions gradually increases especially, and such the increasing degree is more evident at higher temperatures. A brief analysis of these results is given.
