Investigation of strain-engineered electronic structures of GeSe using the First-principles

Germanium selenide (GeSe) is a promising layered semiconductor for optoelectronics. Its bulk form yet a comprehensive understanding of its strain-dependent electronic properties remains underdeveloped, especially compared to its monolayer counterpart. Herein, we present a systematic first-principles study on the evolution of the electronic structure of bulk GeSe under uniaxial strain applied along the zigzag and armchair directions. Like the observations in strained monolayer GeSe, we find that the value of the bandgap is effectively tunable with strain. While the relationship between the gap and the bond length d1 is highly anisotropic, our key discovery is a unified, exponential scaling law governing the bandgap evolution with the bond length d2 for both crystallographic directions. This finding identifies that d2 effectively integrates the lattice information into a single predictive parameter linked to the energy of the conduction band minimum. This work provides a fundamental scaling principle for strain engineering in bulk GeSe, offering a powerful tool for the rational design of its optoelectronic properties.