Mechanical, optoelectronic and transport properties of single-layer Ca2N and Sr2N electrides

Abstract

Electride materials offer attractive physical properties due to their loosely bound electrons.Ca 2 N, an electride in the two-dimensional (2D) form was successfully recently synthesized.We conducted extensive first-principles calculations to explore the mechanical, electronic, optical and transport response of single-layer and free-standing Ca 2 N and Sr 2 N electrides to external strain. We show that Ca 2 N and Sr 2 N sheets present isotropic elastic properties with positive Poisson's ratios, however, they yield around 50% higher tensile strength along the zigzag direction as compared with armchair. We also showed that the strain has negligible effect on the conductivity of the materials; the current in the system reduces by less than 32% for the structure under ultimate uniaxial strain along the armchair direction. Compressive strain always increases the electronic transport in the systems due to stronger overlap of the atomic orbitals. Our results show that the optical spectra are anisotropic for light polarization parallel and perpendicular to the plane. Interband transition contributions along in-plane polarization are not negligible, by considering this effect the optical properties of Ca 2 N and Sr 2 N sheets in the low frequency regime significantly changed. The insight provided by this study can be useful for the future application of Ca 2 N and Sr 2 N in nanodevices.

Periodic trends in the structural, electronic, and transport properties of electrenes

“…11,42,50,51 Moreover, little is known about the transport properties of these materials, with only Ca 2 N and Sr 2 N having been analyzed theoretically. 52,53…”

Type-II Weyl fermion induced hydrogen adsorption in a two-dimensional electride [Ca2N]+·e−

“…Then, Lee et al 6 successfully synthesized the electride [Ca 2 N] + $e À , which extended the electronic crystal from 0D to 2D. Particularly, researchers nd that [Ca 2 N] + $e À possesses a series of interesting properties, such as a low work function, 7 unique light polarization characteristics, 8 excellent catalytic activity, 9 etc.…”

Graphene Oxide Concentration Effect on the Optoelectronic Properties of ZnO/GO Nanocomposites

“…Studies regarding the theoretical evaluation of optoelectronic properties of 2D materials were published previously. It was demonstrated that localization of electronic states plays a key role in determining the properties of the considered systems [ 48 ].…”