New structures of bilayer germanium nanosheets predicted by a particle swarm optimization method.
A global search for the stable structures of bilayer Ge (BLG) is performed, and the most stable and meta-stable BLG structures are predicted for the first time. Phonon-spectrum calculations and ab initio molecular dynamics simulations confirm their dynamical and thermal stability. The computed electronic structures suggest that the most stable structure is metal while the meta-stable structure of BLG is a semiconductor with an indirect band gap (0.32 eV at the level of PBE functional and 0.81 eV at the level of HSE06). By straining the layer plane of the meta-stable BLG, we observe a phase transition from semiconductor to metal. Furthermore, the adsorption of gas molecules of CO, CO2, NH3, NO and NO2 on the meta-stable structure is also studied. Our results show that the predicted meta-stable BLG also possesses a good feature in gas sensors.
Laboratory of Amorphous Materials, School of Materials Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, P. R. China. rlzhou@hfut.edu.cn.
Dongdong
D
Li
Pengfei
P
Li
Bingyan
B
Qu
B C
BC
Pan
B
B
Zhang
H Y
HY
He
Rulong
R
Zhou