Optical and vibrational properties of low-symmetry two-dimensional materials under compressive strain

Due to their remarkable mechanical and electronic properties, twodimensional materials have been the subject of avid interest over the last decade and a half. The successful exfoliation of graphene in 2004 was a watershed moment, prompting search for new monolayered materials that could be used in the next-generation of electronic devices. While many of graphene’s admirable traits—record-setting tensile strength, massless dirac fermions, among others—are a result of its highly symmetric “honeycomb” crystal structure, a new class of monolayered materials with low-symmetry structures has recently been gaining interest. Due to their uniquely anisotropic electronic and thermal properties, low-symmetry materials such as ReS₂ and phosphorene are promising candidate materials for thermoelectric and optoelectronic devices capable of leveraging their anisotropy. In this work, we examine the effect of pressure on monolayer ReS₂ and few-layer phosphorene to determine their suitability for strain-tuned and flexible electronic devices