Anisotropic quantum confinement in interface-defined stanene quantum dots

Quantum dots (QDs) embedded in two-dimensional (2D) materials provide an ideal platform for exploring tunable quantum confinement in real and momentum space. Here, we investigate interface-defined stanene QDs by low-temperature scanning tunneling microscopy and spectroscopy. The QDs form as nanometer-scale confined regions within a continuous stanene monolayer due to buried interfacial SnxO nanopatches. Differential conductance spectra reveal discrete resonant states accompanied by pronounced quantum interference patterns. Spectroscopic mapping along orthogonal crystallographic directions shows strong anisotropy of the confined states, indicating quasi-one-dimensional confinement. The observed energy levels are well described by an effective one-dimensional hard-wall model with a spatially varying potential. These results establish interface-controlled quantum confinement in stanene and demonstrate how buried interfacial structures can fundamentally reshape electronic states in supported 2D Xene materials.