Quantum coherence and relaxation of single spins on surfaces probed by ESR-STM

The miniaturization of modern devices to the nanoscale has inspired the development of quantum information processing, in which quantum coherence is of vital importance for both fundamental research and applications. The integration of electron spin resonance with scanning tunneling microscopy (ESR-STM) has emerged as a powerful platform for atomic-scale quantum sensing, simulation and qubit operations on surfaces. However, the qubit lifetime faces significant challenges due to environmental perturbations in STM circuits, whose underlying mechanisms require a deep and comprehensive understanding. This minireview summarizes recent advances in studying spin coherence using ESR-STM, focusing on the fundamental decoherence pathways including scattering and tunneling electrons and magnetic perturbations near the tunnel junction. By elucidating the microscopic origins of decoherence in atomic and molecular spin systems on surfaces, we provide a framework for developing targeted strategies to enhance the quantum coherence of spin qubits on surfaces.