Liu Xiaofeng, Ding Zijing, Liu Jie, Hu Wei, Yang Jinlong
Hefei National Laboratory for Physical Sciences at Microscale, Department of Chemical Physics, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
Nanoscale. 2020 Mar 5;12(9):5578-5586. doi: 10.1039/c9nr10765g.
Electrides possess high electrical conductance and reactivity and are promising for novel applications in electronics and catalysis. Here, we predict a new thermodynamically and kinetically stable two-dimensional (2D) Ca4N2 using first-principles density functional theory (DFT) calculations. 2D Ca4N2 can serve as a one-dimensional (1D) electride [Ca4N2]2+·2e- with anionic electrons confined in the surface channels. In particular, we demonstrate that 2D Ca4N2 possesses high Fermi velocity (0.42 × 106 m s-1), electron effective Fermi mass (∼1me), ultrahigh charge density (1.14 × 1015 cm-2), and high carrier mobility (215 and 5.29 × 106 cm2 V-1 s-1 at a room temperature of 300 K and a low temperature of 2 K), resulting in ultrahigh conductance up to 0.039 and 966 S respectively for 300 and 2 K, compared to existing 2D materials and the best conductors (Cu and Ag). Furthermore, the first finding of 1D anionic electron behaviour on the surface of 2D materials can be used to stimulate the design of new kinds of electrides for exploring the physics of 1D and quasi-1D systems.
电子化物具有高电导率和反应活性，在电子学和催化领域有着广阔的新应用前景。在此，我们利用第一性原理密度泛函理论（DFT）计算预测了一种新的热力学和动力学稳定的二维（2D）Ca4N2。二维Ca4N2可作为一维（1D）电子化物[Ca4N2]2+·2e-，其阴离子电子被限制在表面通道中。特别地，我们证明二维Ca4N2具有高费米速度（0.42×106 m s-1）、电子有效费米质量（~1me）、超高电荷密度（1.14×1015 cm-2）和高载流子迁移率（在300 K室温及2 K低温下分别为215和5.29×106 cm2 V-1 s-1），与现有二维材料和最佳导体（铜和银）相比，在300 K和2 K时分别产生高达0.039和966 S的超高电导率。此外，二维材料表面一维阴离子电子行为的首次发现可用于激发新型电子化物的设计，以探索一维和准一维系统的物理特性。
