Fig. 2: LZSM interference of a single Ti spin.
From: Electrically tunable quantum interference of atomic spins on surfaces
a Schematics of the pulse sequences for the LZSM measurement. Both \({V}_{{{\rm{bias}}}}\) and \({V}_{{{\rm{RF}}}}\) are sinusoidal in time. \({V}_{{{\rm{DC}}}}\) and \(\delta V\) are the DC component and modulation amplitude of \({V}_{{{\rm{bias}}}}\). The polarity of \({V}_{{{\rm{bias}}}}\) is indicated by + (red regions) and – (blue regions) signs. b–d ESR spectra as a function of detuning \({\omega }_{{{\rm{RF}}}}-{\omega }_{0}\) and modulation frequency \(f\), measured at a fixed modulation amplitude \(\delta V\) of 140, 60 and 20 mV, respectively (\({V}_{{{\rm{DC}}}}\) = −50 mV, \({V}_{{{\rm{RF}}}}\) = 20 mV; \({B}_{{{\rm{ext}}}}\) = 0.58 T; setpoint: \({V}_{{{\rm{sp}}}}\) = 50 mV, \({I}_{{{\rm{sp}}}}\) = 60 pA). The multiphoton resonances at \(\left|{\omega }_{{{\rm{RF}}}}-{\omega }_{0}\right|/2{{\rm{\pi }}}={nf}\) are labeled, and also indicated by red dashed lines. Dashed white lines indicate the onset of motional averaging. Red arrows in b indicate the two main peaks at slow modulation. The detuning shift is ~1.9 MHz/mV for the STM tip used. e, f ESR spectra measured at low modulation frequencies \(f\) with positive (e) and negative (f) DC voltages \({V}_{{{\rm{DC}}}}\) (\({V}_{{{\rm{DC}}}}\) = 50, −40 mV, \(\delta V\) = 100, 80 mV, \({V}_{{{\rm{RF}}}}\) = 15 mV; \({B}_{{{\rm{ext}}}}\) = 0.52 T; setpoint: \({V}_{{{\rm{sp}}}}\) = 50 mV, \({I}_{{{\rm{sp}}}}\) = 50 pA). The lower panels show the ESR spectra at \(f\) = 13 MHz.
