SEMICONDUCTOR PHYSICS

Quantum pump effect in a four-terminal mesoscopic structure

Kaikai Wang

+ Author Affiliations

 Corresponding author: Kaikai Wang, E-mail: kkwang@semi.ac.cn

PDF

Abstract: Quantum pump effect in a four-terminal mesoscopic structure constructed from a homogeneous two-dimensional electron gas is investigated. Oscillating electric potentials are applied to the two opposite terminals of the four-terminal mesoscopic structure. In both the remaining two opposite terminals and in the central region there are constant potentials that do not change with time. The oscillating potentials change slowly in comparison with all of the internal time scales of the structure and the amplitude of the oscillating potentials is small in comparison with the Fermi energy. The current of each lead and the transmission coefficients from one lead to another are calculated by using the non-equilibrium Green's function approach under the adiabatic approximation. In the remaining two opposite terminals of the four-terminal structure, the quantum pump effect can produce an electric current whose magnitude and direction depends on the Fermi energy. The pumped currents are ascribed to the asymmetry of transmission coefficients with respect to the Fermi energy.

Key words: quantum pump effectmesoscopic structure



[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
Fig. 1.  Schematic diagram for the four-terminal structure. Oscillating electric potentials are applied to the two opposite terminals (lead-1 and lead-2) of the four-terminal structure. The electric potentials of the remaining two opposite terminals (lead-3 and lead-4) are equal to that of the central region.

Fig. 2.  (Color online) (a) The currents in lead-1 and lead-2 versus $\omega\tau$, and (b) the currents in lead-3, lead-4 and the total current of four leads versus $\omega\tau$ with the size of central region $L=18a$, the Fermi energy $E_{\rm F}=-3.80t$ and the amplitude of the oscillating electric potential $\Delta=0.02t$. The parameter $\omega\tau$ ranges from 0 to $4\pi$.

Fig. 3.  (Color online) Transmission coefficients from lead-3 to lead-1 (2, 4) and from lead-1 to lead-2 versus energy $\varepsilon$ with the size of central region $L=18a$. The energy $\varepsilon$ ranges from $-4.00t$ to $-3.20t$.

DownLoad: CSV
DownLoad: CSV
DownLoad: CSV
DownLoad: CSV
DownLoad: CSV
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
[18]
[19]
[20]
[21]
[22]
[23]
  • Search

    Advanced Search >>

    GET CITATION

    shu

    Export: BibTex EndNote

    Article Metrics

    Article views: 632 Times PDF downloads: 15 Times Cited by: 0 Times

    History

    Received: 07 July 2014 Revised: Online: Published: 01 February 2015

    Catalog

      Email This Article

      User name:
      Email:*请输入正确邮箱
      Code:*验证码错误
      Kaikai Wang. Quantum pump effect in a four-terminal mesoscopic structure[J]. Journal of Semiconductors, 2015, 36(2): 022002. doi: 10.1088/1674-4926/36/2/022002 K K Wang. Quantum pump effect in a four-terminal mesoscopic structure[J]. J. Semicond., 2015, 36(2): 022003. doi: 10.1088/1674-4926/36/2/022003.Export: BibTex EndNote
      Citation:
      Kaikai Wang. Quantum pump effect in a four-terminal mesoscopic structure[J]. Journal of Semiconductors, 2015, 36(2): 022002. doi: 10.1088/1674-4926/36/2/022002

      K K Wang. Quantum pump effect in a four-terminal mesoscopic structure[J]. J. Semicond., 2015, 36(2): 022003. doi: 10.1088/1674-4926/36/2/022003.
      Export: BibTex EndNote

      Quantum pump effect in a four-terminal mesoscopic structure

      doi: 10.1088/1674-4926/36/2/022002
      More Information
      • Corresponding author: E-mail: kkwang@semi.ac.cn
      • Received Date: 2014-07-07
      • Accepted Date: 2014-08-06
      • Published Date: 2015-01-25

      Catalog

        /

        DownLoad:  Full-Size Img  PowerPoint
        Return
        Return