Nanoelectronic Devices for Low Temperature Thermometry

The ability to cool materials to millikelvin temperatures has been the foundation of many breakthroughs in solid state physics and nanotechnology. At this frontier, quantum behaviour can be studied by making devices smaller and colder, thereby increasing coherence across the system.

As experiments are pushed into the sub-millikelvin regime, it becomes increasingly difficult to measure and define the temperature of a system. At these temperatures the thermal coupling between various sub-systems in a device can be extremely small. This may mean, for instance, that the electrons in the metal wires contacting an on-chip structure are at a different temperature to the electrons in the chip, the phonons in the chip, and even the apparatus that you are using to cool it. This situation calls for a variety of thermometry techniques, each one suited to measuring the temperature of a different physical system. Such thermometers must also have extremely low heat dissipation, and excellent isolation from the room temperature environment.

The goal of this project is to design, fabricate, and characterise new types of sub-millikelvin thermometers based on nanoelectronic and nanomechanical devices. By building such thermometers, we aim to access a new regime in nanoscale physics. The devices will be produced in the Lancaster Quantum Technology Centre cleanroom and cooled to microkelvin temperatures using the cutting-edge facilities of the Ultralow Temperature group at Lancaster. The successful applicant will acquire skills in nanofabrication and ultralow temperature electrical measurements.