Li Sheng-shi, Zhang Chang-wen, Ji Wei-xiao, Li Feng, Wang Pei-ji, Hu Shu-jun, Yan Shi-shen, Liu Yu-shen
School of Physics and Technology, University of Jinan, Jinan, Shandong 250022, People's Republic of China.
Phys Chem Chem Phys. 2014 Aug 14;16(30):15968-78. doi: 10.1039/c4cp01211a.
We performed first-principles calculations to study the adsorption characteristics of alkali, alkali-earth, group III, and 3d transition-metal (TM) adatoms on germanene. We find that the adsorption of alkali or alkali-earth adatoms on germanene has minimal effects on geometry of germanene. The significant charge transfer from alkali adatoms to germanene leads to metallization of germanene, whereas alkali-earth adatom adsorption, whose interaction is a mixture of ionic and covalent, results in semiconducting behavior with an energy gap of 17-29 meV. For group III adatoms, they also bind germanene with mixed covalent and ionic bonding character. Adsorption characteristics of the transition metals (TMs) are rather complicated, though all TM adsorptions on germanene exhibit strong covalent bonding with germanene. The main contributions to the strong bonding are from the hybridization between the TM 3d and Ge pz orbitals. Depending on the induced-TM type, the adsorbed systems can exhibit metallic, half-metallic, or semiconducting behavior. Also, the variation trends of the dipole moment and work function with the adsorption energy across the different adatoms are discussed. These findings may provide a potential avenue to design new germanene-based devices in nanoelectronics.
我们进行了第一性原理计算，以研究碱金属、碱土金属、Ⅲ族和3d过渡金属（TM）吸附原子在锗烯上的吸附特性。我们发现，碱金属或碱土金属吸附原子在锗烯上的吸附对锗烯的几何结构影响极小。碱金属吸附原子向锗烯的大量电荷转移导致锗烯金属化，而碱土金属吸附原子的吸附，其相互作用是离子键和共价键的混合，导致具有17 - 29毫电子伏特能隙的半导体行为。对于Ⅲ族吸附原子，它们也以共价键和离子键混合的特性与锗烯结合。过渡金属（TMs）的吸附特性相当复杂，尽管所有TM在锗烯上的吸附都表现出与锗烯的强共价键。这种强键合的主要贡献来自TM 3d和Ge pz轨道之间的杂化。根据诱导TM的类型，吸附体系可以表现出金属、半金属或半导体行为。此外，还讨论了不同吸附原子的偶极矩和功函数随吸附能的变化趋势。这些发现可能为纳米电子学中设计新型锗烯基器件提供一条潜在途径。
