Two-dimensional GeAsSe with high and unidirectional conductivity.

Prompted by the recent passion for researching two-dimensional materials, we investigate again the long-forgotten layered semiconductor material GeAsSe. A small cleavage energy (0.18 J m-2) and high thermal stability (1300 K) in monolayer structures were proved by employing density functional theory calculations. Additionally, the unusual electronic transport behaviors in GeAsSe make it more valuable for research. Our investigation proves unidirectional electronic transportation in GeAsSe. At room temperature (300 K), the transport ability of monolayer GeAsSe in the y direction is about 44 times larger than that in the x direction. Furthermore, through layer stacking, the conductivity of bilayer GeAsSe is improved to 192 cm2 V-1 s-1 in the y direction which is 200 times larger than that in the x direction (0.96 cm2 V-1 s-1), implying unidirectional conductivity. This work suggests that two-dimensional GeAsSe is a promising material for nano-electronic devices.