Superconducting-semiconductor quantum devices: from qubits to particle detectors

TL;DR

This paper explores the development of superconducting semiconductor devices, including qubits and particle detectors, using advanced atomistic fabrication techniques on materials like silicon and germanium, with potential for low-noise and novel physics applications.

Contribution

It proposes a method to construct superconducting devices within single-crystal semiconductors using atomistic fabrication, enabling new device designs and applications in quantum computing and particle detection.

Findings

Design parameters for superconducting wires and Josephson junctions in silicon.

Feasibility of realizing transmon and phase-slip qubits in super-silicon.

Potential for high-sensitivity particle detectors based on kinetic inductance.

Abstract

Recent improvements in materials growth and fabrication techniques may finally allow for superconducting semiconductors to realize their potential. Here we build on a recent proposal to construct superconducting devices such as wires, Josephson junctions, and qubits inside and out-of single crystal silicon or germanium. Using atomistic fabrication techniques such as STM hydrogen lithography, heavily-doped superconducting regions within a single crystal could be constructed. We describe the characteristic parameters of basic superconducting elements---a 1D wire and a tunneling Josephson junction---and estimate the values for boron-doped silicon. The epitaxial, single-crystal nature of these devices, along with the extreme flexibility in device design down to the single-atom scale, may enable lower-noise or new types of devices and physics. We consider applications for such super-silicon devices, showing that the state-of-the-art transmon qubit and the sought-after phase-slip qubit can both be realized. The latter qubit leverages the natural high kinetic inductance of these materials. Building on this, we explore how kinetic inductance based particle detectors (e.g., photon or phonon) could be realized with potential application in astronomy or nanomechanics. We discuss super-semi devices (such as in silicon, germanium, or diamond) which would not require atomistic fabrication approaches and could be realized today.