Radio-Frequency Charge Detection on Graphene Electron-Hole Double Quantum Dots.

Hecker, K; Möller, S; Dulisch, H; Duman, Ş; Stecher, L; Valerius, L; Deußen, T; Ravuri, S et al. · Nano Lett · 2025

basic_science · Level V

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Abstract

High-fidelity detection of charge transitions in quantum dots (QDs) is a key ingredient in solid-state quantum computation. We demonstrate high-bandwidth radio-frequency charge detection in bilayer graphene quantum dots (QDs) using a capacitively coupled quantum point contact (QPC). The device design suppresses screening effects and enables a sensitive QPC-based charge readout. The QPC is arranged to maximize the readout contrast between two neighboring coupled electron and hole QDs. We apply the readout scheme to a single-particle electron-hole double QD and demonstrate time-resolved detection of charge states as well as magnetic field dependent tunneling rates. This promises a high-fidelity readout scheme for individual spin and valley states, which is important for the operation of spin, valley, or spin-valley qubits in bilayer graphene.