C59-27(c) Low-noise deep-cryogenic amplifier based on hydrodynamic charge transport in GaAs/AlGaAs

Heat dissipation and noise are critical issues for electronics used in deep-cryogenic (10-100 milli-Kelvin) High Energy Physics experiments, wherein the cooling power is limited to 1 milli-Watt. However, High-Electron Mobility Transistor amplifiers dissipate 10 milli-Watts, restricting their use to above 4 Kelvin. To enable integration of hundreds of thousands of sensors planned in future CMB experiments requires a replacement for HEMTs that dissipates much less heat, so that it can be co-located with quantum sensors at mK temperatures. Proposed is a quantum-noise limited deep-cryogenic amplifier that is 10-100 times more efficient than present amplifiers, allowing for usage in milli-Kelvin temperatures. The proposed amplifier exploits highly-efficient electron-electron scattering that leads to hydrodynamic charge transport in two-dimensional electron gasses, realized in high mobility heterostructures of Gallium Arsenide and Aluminium Gallium Arsenide. The overall objective of Phase I is to establish a device design that achieves a greater-than-unity gain using hydrodynamic charge transport in high mobility heterostructures of Gallium Arsenide and Aluminium Gallium Arsenide. The Phase I work involves (1) studying the dependence of the device geometry on the essential nonlinearity (due to electron-electron scattering) that underlies amplification, (2) impedance engineering to match with a 50 Ohm environment, (3) gain and noise characterization, (4) development of a computational model to optimize the device design in Phase II. A successful demonstration of amplification will introduce a new paradigm for highly-performant cryo-compatible electronics on a number of metrics (power efficiency, heat dissipation, noise, frequency bandwidth), while also being easier to manufacture; the new design paradigm only requires two-dimensional lithography. The extremely low dissipation of the proposed amplifier will enable large-scale integration of quantum sensors leading to a vast improvement in the capability of upcoming Cosmic Microwave Background measurements and dark matter searches, potentially uncovering new physics and ultimately expanding our understanding of the universe.