Fig. 1: Growth process of K3P films.
From: Atomic-scale electrostatic engineering of flat bands in a K3P Lieb lattice
a, b Close-up (V = −50 mV, I = 1.5 nA) and large-area (V = 1 V, I = 0.1 nA) scanning tunneling microscopy (STM) images of the clean Au(111) substrate. The phosphorus (P) source material is evaporated on the surface in the form of P4 molecules. c, d Close-up (V = 50 mV, I = 1 nA) and large-area (V = 0.1 V, I = 50 pA) STM images of the Au9P18 film. The film periodicity of 1.45 nm is marked by a white rhombus, and its atomic structure is shown in the inset of panel (c). Potassium (K) atoms were deposited onto the Au9P18 film followed by annealing to synthesize K3P. e, f Close-up (V = 100 mV, I = 0.8 nA) and large-area (V = −1.2 V, I = 0.3 nA) STM images of the K3P lattice. K3P exhibits a square unit cell with a lattice constant of 6.2 Å, as marked by the white square. The color bar codes for the topographic height (L: low, H: high). Scale bar: a 0.6 nm; b 15 nm; c 1 nm; d 14 nm; e 0.6 nm; f 3 nm.
