Fig. 3: Topography, dI/dV spectroscopy, and spatial mapping of NV- defect wavefunctions in diamond.
From: Atomic-scale imaging and charge state manipulation of NV centers by scanning tunneling microscopy
a–d Topography (VBias = -900 mV, ISetpoint = 100 pA), dI/dV spectrum (VBias = 900 mV, ISetpoint = 100 pA) and two dI/dV map (VBias = 900 mV, ISetpoint = 100 pA) slices at -300 mV and +300 mV of an NV- defect, labeled Defect 4. A clear asymmetric double-lobe structure can be seen in the density-of-states at the peak energy of -300 mV, while no structure is visible at +300 mV. e–h Topography (VBias = -1.00 V, ISetpoint = 70 pA), dI/dV spectrum (VBias = -1.20 V, ISetpoint = 70 pA) and two dI/dV map (VBias = -1.20 V, ISetpoint = 70 pA) slices at -360 mV and +360 mV of another NV- defect, labeled Defect 5, on the same sample and probed with the same STM tip as Defect 4. Again, an asymmetric double-lobe structure can be seen in the negative energy density-of-states at the peak energy of -360 mV but has a different directionality from Defect 4, showing that the spatial structures of the defect wavefunction are not due to tip-shape effects. The dI/dV slice at positive bias again shows no structure. We find that the defects we image are along the diamond [111] direction projected to the (100) surface ([011], [\(0\bar{1}1\)]), in agreement with the expected directionality of NV-centers. The diamond lattice directions are labeled in (a). All scale bars in this figure are 0.5 nm.
