Zhou Fei, Liu Yong, Lai Zhonghong, Liao Mingqing, Zhou Yi, Huang Yudong, Zhu Jingchuan
School of Materials Science and Engineering, Harbin Institute of Technology 150001 Harbin China
MIIT Key Laboratory of Critical Materials Technology for New Energy Conversion and Storage, School of Chemistry and Chemical Engineering, Harbin Institute of Technology 150001 Harbin China.
RSC Adv. 2018 Jun 5;8(37):20477-20482. doi: 10.1039/c8ra03928c.
The Polar discontinuity at heterointerface and the bare surface reconstructs the electronic phase of perovskite oxides. This gives rise to confined free electrons which intrinsically transit material from band insulator to metal. However, the insulator-metal transition induced by free holes has not been investigated so far due to the challenge in obtaining free hole state in oxides. Here, we propose a simple method whereby free holes can be obtained polar facet reorientation. In the high polarity case, free holes can be supported by the lift up of O 2p subbands, which split into three independent subbands (one heavy hole subband and two light hole subbands) due to strong quantum confinement. Results show that both of the free electron and hole states are confined in a two dimensional quantum well, subjecting to the confined energy ( - ) and occupied density of states around the Fermi level, indicating a finite thickness for preserving the metal states.
异质界面和裸露表面处的极性不连续性重构了钙钛矿氧化物的电子相。这产生了受限的自由电子，其本质上使材料从带绝缘体转变为金属。然而，由于在氧化物中获得自由空穴态存在挑战，迄今为止尚未对由自由空穴诱导的绝缘体 - 金属转变进行研究。在此，我们提出一种简单的方法，通过极性面重取向可以获得自由空穴。在高极性情况下，自由空穴可以由O 2p子带的提升来支持，由于强量子限制，O 2p子带分裂成三个独立的子带（一个重空穴子带和两个轻空穴子带）。结果表明，自由电子和空穴态都被限制在二维量子阱中，受限于受限能量（ - ）和费米能级周围的占据态密度，这表明保持金属态需要有限的厚度。
