Fig. 1: Cooling electrons in a 2DEG in 3He immersion cells.
From: Cooling low-dimensional electron systems into the microkelvin regime
a Schematic of the sample: the 2DEG is created at a GaAs/AlGaAs heterojunction, and electrical connections are provided by AuNiGe ohmic contacts. b Top view of the 4 mm × 4 mm device cooled to 1 mK by the I± and V± ohmic contacts, also used to measure the electrical resistances in the device. A noise thermometer (NT) is connected to the NT ohmic contact to probe the electron temperature Te. c Progressive cooling of the 2DEG device in plastic (d) and metal (e) immersion cells equipped with different low-pass filters. Te is estimated from Eq. (4), assuming that the 3He bath is at temperature Tbath = 0.3 mK.
