Cryotronics

Cryotronics is a branch of electronics that studies and applies electronic devices and circuits at cryogenic temperatures, typically from a few kelvin up to tens of kelvin, and sometimes into the millikelvin range. It unites cryogenics, materials science, and electrical engineering to understand how electrical transport, noise, and device performance change as thermal energy is removed and quantum effects emerge.

The field encompasses superconducting electronics, cryogenic sensors, and the electronics needed to operate and read out low-temperature systems. Core topics include superconducting devices such as Josephson junctions and SQUIDs, cryogenic semiconductor devices, and quantum-information hardware based on superconducting qubits. It also covers high-sensitivity detectors such as bolometers and calorimeters used in astronomy and particle physics.

Techniques and infrastructure include cryostats and refrigeration (liquid helium systems and dilution refrigerators), thermal management and shielding, and low-noise cryogenic amplifiers and filters. Researchers characterize material properties at low temperatures, including resistivity, carrier mobility, superconducting transitions, and electron-phonon interactions, to optimize performance and reliability of cryogenic circuits.

Cryotronics has enabled advances in metrology and sensing, including ultra-sensitive magnetometers, low-noise readout for quantum devices, and detectors for astrophysical observations. The field supports research in condensed-matter physics, quantum information science, and various applied technologies such as medical imaging and space science.