A scanning tunneling microscope capable of electron spin resonance and pump-probe spectroscopy at mK temperature and in vector magnetic field

A theoretical review on the single-impurity electron spin resonance on surfaces

“…Even if the orbital degrees of freedom of the adatom were playing supplying the required angular momentum, it would not explain why the magnetic resonance is visible for bias voltages way below the orbital angular momentum excitation threshold [55]. Moreover, it seems that this mechanism works even in the absence of spin-polarization, in clear contrast to the experiments [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. Moreover, the standoff distance dependence observed experimentally [20] for Fe and Ti-H on MgO/Ag could not be explained by this deformation potential.…”

“…The growing number of experimental results on STM-ESR is starting to delineate the role of the different experimental variables that control the resonance signal. They have clarified the relevance of the DC and RF bias voltage, the tunnel conductance, the temperature, or some of the tip microscopic details [12,20,21].…”

“…Balatsky et al proposed a mechanism where the modulation of the tunnel barrier was mediated by the spin-orbit interaction of the substrate-metal conduction electrons [74]. This effect translates into a current-independent modulation of the density of states by the precessing spin, which should work even in the absence of current spin-polarization, in contrast with the broadly accepted STM-ESR measurements [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23]. The modulation of the tunneling barrier by the electric dipole moment originating from the spin-orbit interaction was also considered by Shachal and Manassen [75], but this effect was later estimated to be negligible [76].…”

A millikelvin scanning tunneling microscope in ultra-high vacuum with adiabatic demagnetization refrigeration

“…Scanning tunneling microscopy (STM) performed in ultrahigh vacuum (UHV) at millikelvin (mK) temperatures enables studies of delicate quantum phenomena that occur on surfaces [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] . The growing interest in phenomena like quantum entanglement will most probably boost the demand for mK STM instrumentation.…”