Abstract：We investigate the heat generation $Q$ in a quantum dot (QD), coupled to a normal metal and a superconductor, without electric bias voltage. It is found that $Q$ is quite sensitive to the lead temperatures $T_{\rm L,R}$ and the superconductor gap magnitude ${\it \Delta}$. At $T_{\rm L,R}\ll \omega_0$ ($\omega_0$ is the phonon frequency), the superconductor affects $Q$ only at ${\it \Delta} < \omega_0$, and the maximum magnitude of negative $Q$ appears at some ${\it \Delta}$ slightly smaller than $\omega_0$. At elevated lead temperature, contribution to $Q$ from the superconductor arises at ${\it \Delta}$, ranging from less than to much larger than $\omega_0$. However, the peak value of $Q$ is several times smaller than that in the case of $T_{\rm L,R}\ll \omega_0$. Interchanging lead temperatures $T_{\rm L}$ and $T_{\rm R}$ leads to quite different $Q$ behaviors, while this makes no difference for a normal-metal–quantum-dot–normal-metal system, and the QD can be cooled much more efficiently when the superconductor is colder.
(Electronic transport in nanoscale materials and structures)
引用本文:
. [J]. 中国物理快报, 2017, 34(6): 67101-.
Li-Ling Zhou, Xue-Yun Zhou, Rong Cheng, Cui-Ling Hou, Hong Shen. Local Heating in a Normal-Metal–Quantum-Dot–Superconductor System without Electric Voltage Bias. Chin. Phys. Lett., 2017, 34(6): 67101-.
2017, Vol. 34 
