Hebei Normal College for Nationalities

Hebei, China

Hebei Normal College for Nationalities

Hebei, China
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Wang S.-X.,Hebei Normal College for Nationalities | Wang S.-X.,Hebei Advanced Film Laboratory | Li Z.-W.,Hebei Normal College for Nationalities | Li Z.-W.,Hebei Advanced Film Laboratory | And 2 more authors.
Chinese Physics B | Year: 2011

We study electrons tunneling through a double-magnetic-barrier structure on the surface of monolayer graphene. The transmission probability and the conductance are calculated by using the transfer matrix method. The results show that the normal incident transmission probability is blocked by the magnetic vector potential and the Klein tunneling region depends strongly on the direction of the incidence electron. The transmission probability and the conductance can be modulated by changing structural parameters of the barrier, such as width and height, offering a possibility to control electron beams on graphene. © 2011 Chinese Physical Society and IOP Publishing Ltd.


Wang S.,Hebei Normal College for Nationalities | Jing J.,Cheng De Cui Qiao School | Li C.,Hebei Normal College for Nationalities | Du J.,Hebei Normal College for Nationalities
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2011

In this paper the properties of tunneling conductance in ferromagnetic/semiconductor/ferromagnetic heterojunction with double δ barriers are investigated. The results indicate that the tunneling conductance shows behavior of periodic oscillation with equal amplitudes while the size of semiconductor increasing. The strength of δ barrier and the magnetic field as well as the Rashba spin-orbit interaction all have effects on the tunneling conductance.


Du J.,Hebei Normal College for Nationalities | He W.,Hebei Normal University | Xu M.,Shijiazhuang Environmental Monitoring Center
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2010

The transmission probability and probability current density show periodic variations as the quantum ring increases. In the upper arm, the probability current density increases as the δ barrier increases. However, the probability current density decreases as the δ barrier increases in the lower arm. The transmission probability and probability current density show periodic variations as the AB flux increases. The probability current density in the left part of the upper arm and that in the right part of the upper arm are symmetrical under certain condition.


Wang S.,Hebei Normal University | Wang S.,Hebei Normal College for Nationalities | Han J.,Hebei Normal College for Nationalities | Yuan A.,Hebei Normal College for Nationalities
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2011

Transport properties in a graphene-based single square-barrier structure are investigated by using the transfer-matrix technique. The transmission probability and the angularly averaged conductance through the structure have been calculated and analyzed. The relations between transmission probability and the Fermi energies, the barrier width as well as the barrier height are revealed. By making a comparison of angularly averaged conductance in different Fermi energies and structural parameters, the conductance properties are revealed. These results are helpful in designing Nano devices based on graphene.


Du J.,Hebei Normal College for Nationalities | Wang S.,Hebei Normal College for Nationalities | Pan J.,Guangxi Normal University
Journal of Semiconductors | Year: 2011

A new model of metal/semiconductor/metal double-quantum-ring connected in series is proposed and the transport properties in this model are theoretically studied. The results imply that the transmission coefficient shows periodic variations with increasing semiconductor ring size. The effects of the magnetic field and Rashba spin-orbit interaction on the transmission coefficient fortwokinds of spin state electrons are different. The number of the transmission coefficient peaks is related to the length ratio between the upper arm and the half circumference of the ring. In addition, the transmission coefficient shows oscillation behavior with enhanced external magnetic field, and the Corresponding average value is related to the two leads' relative position.


Du J.,Hebei Normal College for Nationalities | Wang S.,Hebei Normal College for Nationalities | Pan J.,Guangxi Normal University | Duan X.,Hebei Polytechnic University
Journal of Semiconductors | Year: 2011

A new model of a triple-terminal quantum ring with three arms is proposed. We develop an equivalent method for reducing the triple-terminal quantum ring to the double-terminal quantum ring and calculate the persistent spin currents in this model. The results indicate that the persistent spin currents show behavior of nonperiodic and unequal amplitude oscillation with increasing semiconductor ring size when the total magnetic flux is zero. However, when the total magnetic flux is non-zero, the persistent spin currents make periodic equal amplitude oscillations with increasing AB magnetic flux intensity. At the same time, the two kinds of spin state persistent spin currents have the same frequency and amplitude but the inverse phase. In addition, the Rashba spin-orbit interaction affects the phase and the phase difference of the persistent spin currents. The average persistent spin currents relate to the arm length and the terminal position as well as the distribution of the magnetic flux in each arm. Furthermore, our results indicate that the AB magnetic flux has different influences on the two kinds of spin state electrons. © 2011 Chinese Institute of Electronics.


Du J.,Hebei Normal College for Nationalities | Wang S.,Hebei Normal College for Nationalities
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2010

The tunneling conductance and the tunneling magnetoresistance in the double quantum ring are studied in this paper. The results indicate that the tunneling conductance and the tunneling magnetoresistance show behavior of periodic iso-amplilude oscillation with the size of the semiconductor ring increasing. The δ barrier, Rashba spin-orbit interaction as well as AB flux all have different effects on tunneling conductance or tunneling magnetoresistance. The tunneling magnetoresistance makes periodic iso-amplitude oscillation with the intension of AB flux enhancing. Furthermore it will increase with the angle φ0 decreasing. But when the direction of the magnetic moment in the two electrodes is antiparalle, the tunneling magnetoresistancet identically equals zero.


Du J.,Hebei Normal College for Nationalities
Guti Dianzixue Yanjiu Yu Jinzhan/Research and Progress of Solid State Electronics | Year: 2010

A model of ferromagnetic/semiconductor/ferromagnetic four-terminal quantum ring is proposed in this paper. The results show that the transmission probability makes periodic equal amplitude oscillation with the size of the semiconductor ring increasing. And it is related to the electron spin orientation together with the magnetic moment direction of each ferromagnetic electrode. The average transmission probability in the upper or in the lower electrode is larger than that in the right one. Whereas the average transmission probability as well as the oscilation frequency for four-terminal quantum ring is less than that for double-terminal quantum ring. Moreover, Rashba spin-orbit coupling can make the transmission probability to be zero and the AB magnetic flux also has influence on it.

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