Strong bulk-surface interaction dominated in-plane anisotropy of electronic structure in GaTe

Recently, intriguing physical properties have been unraveled in anisotropic layered semiconductors, which the in-plane electronic band structure anisotropy often originates from low crystallographic symmetry and thus a thickness-independent character emerges. Here, we apply high-resolution angle-resolved photoemission spectroscopy to directly image energy bands monoclinic gallium telluride (GaTe). Our first-principles calculations reveal of GaTe measured experimentally is dominated by strong bulk-surface interaction rather than geometric factors, surface effect quantum confinement effect. Furthermore, accompanied thickness increasing mono- few-layers, interlayer coupling induces direct-indirect-direct gap transitions hole effective mass reversed. results shed light on origins GaTe, paving way for design device applications nanoelectronics optoelectronics based semiconductors.