C3Al: A tunable bandgap semiconductor with high electron mobility and negative Poisson’s ratio

Abstract

Two-dimensional materials with suitable band gaps and high carrier mobility are considered to be ideal for fabricating next-generation microelectronics devices. In this paper, the C 3 Al crystal structure, electronic and mechanical properties are systematically investigated based on a first-principles method. We find that C 3 Al is an auxetic semiconductor material with wide band gap and high carrier mobility. Electrons have good transport properties but holes are almost completely scattered in the zigzag direction. C 3 Al is one of the few materials with negative Poisson’s ratio effect. In addition, the electronic properties of C 3 Al can transform from semiconductor to metal by tuning straining and stacking. The bare-edge and H-terminated C 3 Al nanoribbons shows an enriched set of electronic properties of semiconductors, half-semiconductor, bipolar magnetic semiconductors , non-magnetic metals, magnetic metals, and half-metals. These results not only provide a theoretically novel and promising crystal configuration, but also further explore the potential of the material for applications in biosensing, strain sensors, transistors, and various nano-optical devices. • The C 3 Al has excellent performance in terms of structural and thermodynamic stability. • C 3 Al is an auxetic semiconductor material with wide band gap and high carrier mobility. • The electronic properties of C 3 Al can transform from semiconductor to metal by tuning strain and stacking. • The bare-edge and H-terminated C 3 Al nanoribbons show an enriched set of electronic properties.