Zhang Wei, Li Feng, Hu Junsong, Zhang Ping, Yin Jiuren, Tang Xianqiong, Jiang Yong, Wu Bozhao, Ding Yanhuai
College of Civil Engineering & Mechanics, Xiangtan University, Hunan 411105, People's Republic of China.
J Phys Condens Matter. 2017 Nov 22;29(46):465501. doi: 10.1088/1361-648X/aa8e7e.
The effects of uniaxial strain on the structure, band gap and transmission carriers of monolayer phosphorene were investigated by first-principles calculations. The strain induced semiconductor-metal as well as direct-indirect transitions were studied in monolayer phosphorene. The position of CBM which belonged to indirect gap shifts along the direction of the applied strain. We have concluded the change rules of the carrier effective mass when plane strains are applied. In band structure, the sudden decrease of band gap or the new formation of CBM (VBM) causes the unexpected change in carrier effective mass. The effects of zigzag and armchair strain on the effective electron mass in phosphorene are different. The strain along zigzag direction has effects on the electrons effective mass along both zigzag and armchair direction. By contrast, armchair-direction strain seems to affect only on the free electron mass along zigzag direction. For the holes, the effective masses along zigzag direction are largely affected by plane strains while the effective mass along armchair direction exhibits independence in strain processing. The carrier density of monolayer phosphorene at 300 K is calculated about [Formula: see text] cm, which is greatly influenced by the temperature and strain. Strain engineering is an efficient method to improve the carrier density in phosphorene.
通过第一性原理计算研究了单轴应变对单层磷烯的结构、带隙和传输载流子的影响。在单层磷烯中研究了应变诱导的半导体-金属转变以及直接-间接跃迁。属于间接带隙的导带极小值（CBM）位置沿外加应变方向移动。我们总结了施加平面应变时载流子有效质量的变化规律。在能带结构中，带隙的突然减小或CBM（价带极大值，VBM）的新形成会导致载流子有效质量发生意外变化。锯齿形和扶手椅形应变对磷烯中有效电子质量的影响不同。沿锯齿形方向的应变对沿锯齿形和扶手椅形方向的电子有效质量都有影响。相比之下，扶手椅形方向的应变似乎仅影响沿锯齿形方向的自由电子质量。对于空穴，沿锯齿形方向的有效质量受平面应变的影响很大，而沿扶手椅形方向的有效质量在应变处理中表现出独立性。计算出单层磷烯在300 K时的载流子密度约为[公式：见原文] cm ，其受温度和应变的影响很大。应变工程是提高磷烯中载流子密度的有效方法。
