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Quasi-2D Ca2X (X = C, Si, Ge, Sn, Pb) hexagonal intermetallic monolayer compounds: Comprehensive and comparative study on the electronic properties and strong anisotropic photo-response

Year: 2025

Type: article

Abstract: Quasi-two-dimensional (2D) materials have garnered significant research interest due to their fascinating physical properties and various potential applications across diverse fields. Here, we investigate the electronic properties and anisotropic photo-response of quasi-2D monolayer hexagonal intermetallic compounds based on ultrathin Ca2X (X = group IVA elements) films using computational tools. The electronic investigations show that these monolayer compounds are indirect band gap semiconductors, except for the Ca2C monolayer, which exhibits metallic features. The calculated density of states (both total and projected) for these compounds corroborates the corresponding electronic band structures. The obtained cohesive energy reveals that the Ca2C is the most stable structure. However, the structural stability is slightly reduced when changing the X-atom from top to bottom in group IVA. The investigated materials exhibit a strong anisotropic dielectric behavior in response to the polarization directions (in-plane and out-of-plane) of the light field. These materials exhibit strong light absorption across the infrared (IR) to visible to low-energy ultraviolet (UV) spectrum. A more intense light absorption is also noticed in the X-ray region. Hence, these are excellent for absorption band-pass and stop filters. The calculated refractive index is the highest for the Ca2C monolayer and exhibits an anisotropic dispersion along the x- and z-directions. Moreover, these materials can also be realized in light polarization-dependent reflection and transmission band filters, which are helpful for antireflective coating materials. The investigated properties indicate that these materials have great potential in numerous optoelectronic device applications.

Source: Results in Physics

DOI: 10.1016/j.rinp.2025.108515

Authors: Vipin Kumar, Jin Seog Gwag, Pushpendra Kumar

Institutions: Yeungnam University, Manipal University Jaipur

Language: English

Topic: 2D Materials and Applications

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $1,920

Funders: National Research Foundation of Korea, Science and Engineering Research Board, Military Institute of Science and Technology