Parallel Quantum-Point-Contacts as High-Frequency-Mixers

TL;DR

This paper demonstrates high-frequency mixing using parallel quantum point-contacts in a two-dimensional electron gas, achieving impedance matching, increased power levels, and low conversion loss at cryogenic temperatures.

Contribution

It introduces a novel double-resist technology for fabricating parallel quantum point-contacts, enhancing their high-frequency mixing performance and impedance matching capabilities.

Findings

Successful operation at liquid helium and nitrogen temperatures

Achieved minimal conversion loss of 13 dB

Enhanced power levels and impedance matching over wide frequency range

Abstract

We present the results of high-frequency mixing experiments performed upon parallel quantum point-contacts defined in the two-dimensional electron gas of an Al_{x}Ga_{1-x}As/GaAs-heterostructure. The parallel geometry, fabricated using a novel double-resist technology, enables the point-contact device to be impedance matched over a wide frequency range and, in addition, increases the power levels of the mixing signal while simultaneously reducing the parasitic source-drain capacitance. Here, we consider two parallel quantum point-contact devices with 155 and 110 point-contacts respectively; both devices operated successfully at liquid helium and liquid nitrogen temperatures with a minimal conversion loss of 13 dB.