Nature of tunneling electron spin resonance of an isolated surface spin

A phenomenological model has been proposed for tunneling electron spin resonance (ESR) of an isolated surface spin situated in a scanning tunneling microscope (STM), which explains the dependence of features (local maxima) of the tunneling current on the radio-frequency (RF) electric field and on the position of the tip with respect to the spin. A crossover of the line shape of the resonance signals, whose nature in weak and strong pumping fields corresponds to Lorentzian and Fano resonances, respectively, has been interpreted. New ESR–STM effects that are linear and nonlinear in the RF field and are promising for developing the methods of controlling spin qubits have been predicted.