Adiabatic quantum pump in a zigzag graphene nanoribbon junction

• 作者: 张林
• 来源期刊: 中国物理B（英文版）
• 关键词: quantum pump zigzag graphene nanoribbon pseudo-parity current
• 年，卷（期）: 2015,（11）
• 页码范围: 117202-1-117202-6
• 页数: 1页
• 语种: 英文
• DOI: 10.1088/1674-1056/24/11/117202

摘要

The adiabatic electron transport is theoretically studied in a zigzag graphene nanoribbon (ZGNR) junction with two time-dependent pumping electric fields. By modeling a ZGNR p–n junction and applying the Keldysh Green’s function method, we find that a pumped charge current is flowing in the device at a zero external bias, which mainly comes from the photon-assisted tunneling process and the valley selection rule in an even-chain ZGNR junction. The pumped charge current and its ON and OFF states can be efficiently modulated by changing the system parameters such as the pumping frequency, the pumping phase difference, and the Fermi level. A ferromagnetic ZGNR device is also studied to generate a pure spin current and a fully polarized spin current due to the combined spin pump effect and the valley valve effect. Our finding might pave the way to manipulate the degree of freedom of electrons in a graphene-based electronic device.