Fig. 3: Size and shape dependence of vacancy bound states.
From: Atomically precise engineering of spin–orbit polarons in a kagome magnetic Weyl semimetal
a–h STM images and the dI/dV spectra for linear vacancy chains (a, b), double column vacancy chains (c, d), triangular vacancies (e, f) and hexagonal vacancies (g, h), respectively. The peaks with highest energy position assigned as primary bound state for each vacancy are highlighted by the arrows in (b), (d), (f) and (h), respectively. i Evolution of primary bound states with vacancy size for different vacancy shapes, showing an exponential energy shift depending on the shape symmetry. j Schematic illustration of hybridization between vacancy bound states. Single vacancy creates bound states inside the gap-like density of states at S surface. The hybridization of the additional vacancy induces a new bound state at higher energy. k Calculated evolution of the bound state with the atomic numbers based on a tight-binding model with a nearest neighbor hopping t, showing similar energy shift with experiments in (i). The ε is calculated energy levels of bound states based on the simple model. It indicates quantum confinement of the vacancy bound states. STM parameters for (a–h): Vs = −400 mV, It = 500 pA, Vmod = 0.2 mV. The error bars in (i) from multiple measurements on the same-geometry vacancies are smaller than 3 meV. The scale bars for (a, c, e, g) correspond to 1 nm.
