Prediction of 2D IV–VI semiconductors: auxetic materials with direct bandgap and strong optical absorption
Kai Ren, Xikui Ma, Xiangjun Liu, Yujing Xu, Wenyi Huo, Weifeng Li, Gang Zhang
Abstract
. Their stabilities were confirmed by first-principles lattice dynamics and molecular dynamics calculations. In particular, all these MX monolayers possess a large bandgap in the range of 2.08-2.65 eV and pronounced anisotropic mechanical properties, which are demonstrated by direction-dependent in-plane Young's moduli and Poisson's ratios. Furthermore, all these 2D MX monolayers possess negative Poisson's ratios (even up to about -0.3 for SiSe). Strong optical absorption is observed in these δ-IV-VI monolayers. These interesting physical properties will stimulate the development of 2D flexible devices based on IV-VI semiconductor monolayers.
Topics & Concepts
MonolayerAuxeticsSemiconductorMaterials scienceBand gapAnisotropyLattice (music)Direct and indirect band gapsPoisson's ratioAbsorption (acoustics)Poisson distributionCondensed matter physicsNanotechnologyCrystallographyOptoelectronicsChemistryOpticsComposite materialPhysicsMathematicsAcousticsStatisticsMXene and MAX Phase Materials2D Materials and ApplicationsCellular and Composite Structures