Fast Hole Tunneling Times in Germanium Hut Wires Probed by Single-Shot Reflectometry

TL;DR

This paper demonstrates fast hole tunneling times in Germanium hut wire quantum dots using single-shot reflectometry, highlighting their potential for spin qubit applications with long coherence times.

Contribution

The study introduces a T-like structure in Germanium hut wires integrated with RF reflectometry to measure hole tunneling times, achieving sub-10 microsecond timescales.

Findings

Hole tunneling times less than 10 microseconds were measured.

The small effective mass of Ge heavy-hole states facilitates rapid tunneling.

The setup enables potential projective spin readout in quantum computing.

Abstract

Heavy holes confined in quantum dots are predicted to be promising candidates for the realization of spin qubits with long coherence times. Here we focus on such heavy-hole states confined in Germanium hut wires. By tuning the growth density of the latter we can realize a T-like structure between two neighboring wires. Such a structure allows the realization of a charge sensor, which is electrostatically and tunnel coupled to a quantum dot, with charge-transfer signals as high as 0.3e. By integrating the T-like structure into a radio-frequency reflectometry setup, single-shot measurements allowing the extraction of hole tunneling times are performed. The extracted tunneling times of less than 10$\mu$s are attributed to the small effective mass of Ge heavy-hole states and pave the way towards projective spin readout measurements.