Electron spin resonance with scanning tunneling microscopy: a tool for an on-surface quantum platform of identical qubits

TL;DR

This paper reviews how electron spin resonance integrated with scanning tunneling microscopy enables atomic-scale control and measurement of qubits, advancing on-surface quantum computing with high precision and coherence.

Contribution

It introduces recent ESR-STM advances, demonstrating multi-qubit control and logic gates at the atomic and molecular scale, establishing a versatile quantum platform.

Findings

Single-spin addressability and control demonstrated

Implementation of multi-qubit logic gates like CNOT and Toffoli

ESR-STM as a tool for quantum coherent science at atomic scale

Abstract

Integration of electron spin resonance (ESR) in a scanning tunneling microscope (STM) has enabled an all-electrical control of atomic and molecular spins on solid surfaces with atomic-scale precision and energy resolution beyond thermal limitations. Further, coherent manipulation and detection of individual spins in an ESR-STM establishes a powerful quantum platform, allowing for the implementation of fundamental quantum logic operations to on-surface identical qubits. In this review, we introduce recent advances of ESR-STM, focusing on its application to atomic-scale qubits and extension to molecular qubit systems. We discuss the principles underlying ESR-STM, followed by single-spin addressability, coherent control via Rabi oscillations, and quantum state readout through frequency-resolved detection. We further demonstrate multi-qubit control architectures enabled by atom manipulation and local magnetic field engineering, culminating in the realization of multi-qubit logic gates such as the Controlled-NOT and Toffoli gates. These implementations highlight the specialty of ESR-STM towards atomic-scale quantum circuits. Indeed, ESR-STM can be an excellent tool to perform and evaluate quantum operations in molecular qubits. The results reviewed in this collection establish ESR-STM as a versatile tool for advancing quantum coherent science at the atomic and molecular level in solid-state environments.