Quantized thermal conductance at low temperatures in quantum wire with catenoidal contacts

The thermal conductance associated with the lowest six types of ballistic phonon modes in quantum wire with catenoidal contacts is investigated. The results show that the cutoff frequency for the four types of acoustic modes is zero while two types of optical modes are of nonzero cutoff frequency. For a perfect quantum wire, a quantized thermal-conductance plateau can be observed. While for the structure with catenoidal contacts, the thermal-conductance plateau is broken and a decrease in thermal conductance appears. The results also show that the reduced thermal conductance contributed from different vibrational modes has different characteristics.