Electronic structure and chemical bonding of the electron-poor II-V semiconductors ZnSb and ZnAs
Electronic structure and chemical bonding of the electron-poor II-V semiconductors ZnSb and ZnAs
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DOI：
10.1103/physrevb.84.125211
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发表时间：
2011-09
影响因子：
3.7
通讯作者：
D. Benson;O. Sankey;U. Häussermann
中科院分区：
文献类型：
--
作者：
D. Benson;O. Sankey;U. Häussermann
具有CdSb结构的二元化合物ZnSb和ZnAs是半导体（II-V族），尽管平均电子浓度（每个原子3.5个）低于四面体键合的III-V族和II-VI族原型系统（每个原子4个）。我们报告了详细的电子结构和化学键分析的基础上的第一性原理计算的ZnSb和ZnAs。ZnSb和ZnAs被与锌掺杂型半导体GaSb、ZnTe、GaAs和ZnSe以及更离子化的、假设的II-V系统MgSb和MgAs进行比较。我们建立了一个明确的共价键合方案ZnSb和ZnAs多中心键合结构实体（菱形环Zn 2Sb 2和Zn 2As 2）连接到彼此的经典的两个中心，两个电子键。这种键合的情况下，只有在II-V族半导体系统中的弱离子性兼容，并出现强烈耦合的CdSb结构类型的稳定性。有人认为，混合的多中心和两个中心键合的化学键合方案类似于硼和富硼化合物，是典型的电子贫sp键合半导体的平均价电子浓度低于4个原子。
The binary compounds ZnSb and ZnAs with the CdSb structure are semiconductors (II-V), although the average electron concentration (3.5 per atom) is lower than that of the tetrahedrally bonded III-V and II-VI archetype systems (4 per atom). We report a detailed electronic structure and chemical bonding analysis for ZnSb and ZnAs based on first principles calculations. ZnSb and ZnAs are compared to the zinc blende type semiconductors GaSb, ZnTe, GaAs, and ZnSe, as well as the more ionic, hypothetical, II-V systems MgSb and MgAs. We establish a clearly covalent bonding scenario for ZnSb and ZnAs where multicenter bonded structural entities (rhomboid rings Zn 2 Sb 2 and Zn 2 As 2 ) are connected to each other by classical two-center, two-electron bonds. This bonding scenario is only compatible with a weak ionicity in II-V semiconductor systems and appears to be strongly coupled to the stability of the CdSb structure type. It is argued that a chemical bonding scenario with mixed multicenter and two-center bonding resembles that of boron and boron rich compounds, and is typical of electron poor sp-bonded semiconductors with average valence electron concentrations below 4 per atom.