We have identified a class of two-dimensional ferroelastic monolayers, denoted as InXY (where X = S, Se; Y = Cl, Br, I), through first-principles calculations. The dynamic, thermal, and mechanical stabilities of these InXY monolayers are validated by phonon dispersion spectra, AIMD calculations, and elastic constants, respectively. These monolayers exhibit semiconducting behavior with bandgaps ranging from 1.94 to 2.85 eV and possess excellent ferroelasticity with strong ferroelastic signals and moderate ferroelastic switching barriers. Notably, the band edge positions of InSBr and InSI monolayers are observed to stride the water redox potentials at pH = 0, indicating their potential as photocatalysts for water splitting in acidic environments. We also explored the effects of biaxial strain on the band edge alignments and photocatalytic performance of these monolayers. Moreover, the InXY monolayers exhibit excellent anisotropic optical absorption across the visible to ultraviolet regions, along with high anisotropic carrier transport. The coupling of ferroelastic and anisotropic properties in these monolayers offers promising opportunities for designing controllable electronic devices, thereby expanding their potential applications in multifunctional materials. Our findings reveal that the InXY monolayers are promising candidates for efficient photocatalytic water splitting and controllable optoelectronic applications.

中文翻译：

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二维铁弹性半导体 InXY （X = S， Se;Y = Cl、Br、I）：具有可调谐电子各向异性的光催化分解水的有前途的候选者


我们已经确定了一类二维铁弹性单分子层，表示为 InXY（其中 X = S， Se;Y = Cl， Br， I），通过第一性原理计算。这些 InXY 单层的动力学、热和机械稳定性分别通过声子色散光谱、AIMD 计算和弹性常数进行验证。这些单层表现出半导体行为，带隙范围为 1.94 至 2.85 eV，并具有出色的铁弹性、强铁弹性信号和中等铁弹性开关势垒。值得注意的是，在 pH = 0 时观察到 InSBr 和 InSI 单层的带边缘位置使水氧化还原电位大步前进，表明它们有可能成为酸性环境中分解水的光催化剂。我们还探讨了双轴应变对这些单层的带边缘排列和光催化性能的影响。此外，InXY 单层膜在可见光到紫外区域表现出优异的各向异性光吸收，以及高各向异性载流子传输。这些单层中铁弹性和各向异性特性的耦合为设计可控电子器件提供了广阔的机会，从而扩大了它们在多功能材料中的潜在应用。我们的研究结果表明，InXY 单层膜是高效光催化分解水和可控光电应用的有前途的候选者。