Thermal transistor and thermometer based on coupled quantum dot and point contact

We propose a three-terminal setup consisting of a Coulomb coupled quantum dot quantum point contact. The source and drain reservoirs are connected to the QPC while the base reservoir is tunnel coupled to the Coulomb blockade quantum dot, which can contain at most one electron. We show that the setup can work as a nanoscale thermal transistor to control the electric or heat current flow in the quantum point contact. Alternatively, by detecting the electric current in the quantum point contact, the setup can also act as the nanoscale thermometer. We calculate the sensitivity and power gain for the transistor and the sensitivity for the thermometer respectively. We derive the operating condition maximizing their respective sensitivities. We show that the resolution in previous experiments on temperature sensing can be further improved if it is tuned to the optimal regime we derived here.