Fig. 5: Application to real data.
From: Dictionary learning in Fourier-transform scanning tunneling spectroscopy
SBD-STM recoveries with increasing density of defects. In the left column, we have conductance maps with Co defects in NaFe1−xCoxAs of a high-quality (T = 71 K, I = 59 pA, Vset = −100 mV, 114 × 114 nm2), f x = 0.015 (T = 6 K, I = −200 pA, Vset = −20 mV, 50.4 × 50.4 nm2), and k x = 0.02 (T = 5.9 K, I = 200 pA, Vset = −50 mV, 250 × 250 nm2) biased at energies of a 40 meV, f 5 meV, and k − 7 meV. The arrows indicate the principal directions of the lattice. In the right column, clockwise from the top left, we have the recovered kernel b, g, l, the recovered activation map c, h, m, the Re-FT of the kernel d, i, n, and the Re-FT of the conductance map e, j, o, for comparison. The recovered kernels have been given 2-fold rotational symmetry, and all activations have been set to 1 to make them more readily visible. The STM spectroscopy maps have been drift corrected as outlined in Supplementary Note 7. Color bars for real-space images are in units of nS, while color bars for Fourier images are in units of nS−1.
