Fig. 3: Systematic tunneling transport spectra of Co adatoms on Cu, Ag and Au(111) surfaces.

a Excellent agreement between the first-principles spectra and those measured with STS at temperatures of 1.2 K¹³, 1.1 K⁴⁴, 6 K¹⁷. b Spin-resolved spectra indicating that spin-polarized spectroscopy can reshape the measured differential conductance, which would help to disentangle the various contributions to the spectra. The total (solid) signal is obtained by the sum of both spin channels, which were shifted for a better visualization and comparison. c Response of the zero-bias anomalies to magnetic fields. The spin-excitation gap opens while the dip moves to larger energies. Large magnetic field are possible in some STS setups (14 T⁴⁵ or even 38 T^46,47). d Proximity effects can be used via neighboring adatoms and by depositing thin films of noble metals on a ferromagnetic substrate, where the magnetic exchange interaction felt by the adatom acts as an effective magnetic field. The experimental data in a adapted with permission from IOP Publishing for Cu¹³ and from the Japan Society of Applied Physics—Copyright (2005) for Au¹⁷ as well as from Nature Publishing Group for Ag⁴⁴.