Pressure‐Driven Intrinsic Quantum Confinement and Semiconducting‐to‐Metallic Transition in the Topological Flat Bands Kagome Nb3Cl8 Compounds

Abstract

AbstractNb3Cl8 is a unique subset of 2D crystalline materials renowned for their Kagome structure and distinctive flat energy bands. These bands contribute to the distinct electronic behavior, rendering Nb3Cl8 a compelling subject for study. In this study, by employing ab initio calculations, the impact of pressure on the electronic properties of Nb3Cl8is scrutinized, yielding valuable insights. Under high pressures, Nb3Cl8 undergoes a transition from a semiconductor state (with a 1.23 eV bandgap) to a metallic one, accompanied by electronic band restructuration. Notably, the flat energy bands are suppressed with increasing pressure. Furthermore, this investigation underscores the distinctive nature of flat energy bands in Nb3Cl8, delving into quantum effects, particularly their association with the quantum confinement of electronic states. The confinement of charge carriers in Nb3Cl8 results in discrete energy levels, corresponding to specific orbitals in the density of states, indicating robust electron confinement. Pressure‐induced changes in the energy gap between these quantized levels suggest a decrease in confinement strength. Consequently, the study lays a robust foundation for future exploration, contributing to the development of innovative electronic devices grounded in quantum confinement effects.