Extension of on-chip thermometry of metal strips toward sub-10 K regime

Abstract

One widely employed method to study thermoelectric effects in nano- and mesoscopic systems is by utilizing on-chip metal strips. However, the standard technique loses sensitivity in the sub-Kelvin temperature regime because the resistance of metal strips saturates. Here, we report a possible solution that can extend the working point from the conventional window (10 to 300 K) down to temperatures below 10 K. This method takes advantage of the unexpected resistance up-turn at T < 10 K in gold strips, presumably due to the Kondo effect. As a demonstration, we apply this technique to study a NbSe2 flake in the superconducting regime (<6 K).