Extended Data Fig. 2: STM/S results of a single interstitial Fe atom in FeTe films.
a–i, STM images (5 × 5 nm2) of the 40-UC FeTe film with a single interstitial Fe atom measured under different Vs. a, Vs = 3.5 V and Is = 1 nA. b, Vs = 1 V and Is = 9 nA. c, Vs = 500 mV and Is = 9 nA. d, Vs = 50 mV and Is = 5 nA. e, Vs = 15 mV and Is = 1 nA. f, Vs = −15 mV and Is = 1 nA. g, Vs = −50 mV and Is = 5 nA. h, Vs = −500 mV and Is = 5 nA. i, Vs = −2 V and Is = 9 nA. j, Colour plot of dI/dV spectra along the red arrow direction in e (that is, the [100] direction) across a single interstitial Fe atom (Vs = 15 mV, Is = 2 nA and Vmod = 0.1 mV). k, Colour plot of dI/dV spectra along the green arrow direction in e (that is, the [110] direction) across a single interstitial Fe atom (Vs = 15 mV, Is = 2 nA and Vmod = 0.1 mV). Several impurity states are resolved near the interstitial Fe atom. The STM images in a–i are acquired using a spin-polarized tip at T = 4.2 K, whereas the dI/dV spectra are obtained using a PtIr tip at T = 310 mK. Scale bars, 1 nm (a–i).
