Figure 1: Structure and electronic properties of paramagnetic CuPc and diamagnetic NiPc adsorbed on Ag(100).
From: Spin coupling and relaxation inside molecule–metal contacts
(a) STM image of single CuPc (top, I=72 pA, Vb=−5 mV) and NiPc (bottom, I=100 pA, Vb=−3 mV), image size 2.5 nm×2.5 nm. The diagram superposed to NiPc indicates the position of the metal (orange), C (grey), N (blue), and H (white) atoms. (b) dI/dV spectra of CuPc (top) and NiPc (bottom) around EF measured on benzene (blue dot) and (c) on Cu and Ni ions (red dot) (setpoint: I=2 nA/1.1 nA, Vb=−100 mV for CuPc/NiPc). Labels denote Kondo resonances of different nature: zero-bias (K), triplet–singlet (Kts), and vibrational (Kv). Black solid lines in c are fits to the data using the sum of Lorentzian (blue) and step functions (shaded). (d) d2I/dV2 spectra of CuPc (top) and NiPc (bottom) measured on Cu and Ni ions. The dashed lines indicate the energy of the step excitations in c, which correspond to the amplitude of the Raman-active vibrational modes of gas-phase CuPc (bars)21. (e) Extended dI/dV spectra of CuPc on benzene and (f) Cu sites (setpoint: I=3 nA, Vb=−2 V). (g) dI/dV maps of the molecular orbitals and inelastic vibrational signal shown in e and f together with the d2I/dV2 map of the Kondo resonance. The intensity in each map is scaled independently for maximum contrast.
