Spin-dependent tunneling through a symmetric semiconductor barrier

Perel, V. I.; Tarasenko, S. A.; Yassievich, I. N.; Ganichev, Sergey; Belkov, Vassilij; Prettl, Wilhelm

doi:10.1103/physrevb.67.201304

Cited by 203 publications

(162 citation statements)

References 13 publications

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“…H D describes the Dresselhaus spin-orbit coupling, σ α are the Pauli matrices, and γ i (i = 1, 2) describe the strength of the Dresselhaus effect in the contact regions and the barrier. We assume that the kinetic energy of the electron is substantially smaller than the barrier height V in the barrier [7,8] (we take V = 0.2eV , E F = 0.02eV in our paper). The Hamiltonian in the barrier is simplified to…”

Section: (2004))mentioning

confidence: 99%

Spin-dependent tunneling through a symmetric semiconductor barrier: The Dresselhaus effect

et al. 2005

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Spin-dependent tunneling through a symmetric semiconductor barrier is studied including the k 3 Dresselhaus effect. The spin-dependent transmission of electron can be obtained analytically.By comparing with previous work(Phys. Rev. B 67. R201304 (2003) and Phys. Rev. Lett. 93. (2004)), it is shown that the spin polarization and interface current are changed significantly by including the off-diagonal elements in the current operator, and can be enhanced considerably by the Dresselhaus effect in the contact regions.PACS numbers: 72.25. Dc, 72.25.Mk, 73.40.Gk * Correspondence should be sent to: kchang@red.semi.ac.cn 1 Recently electron spin in semiconductors has attracted a rapidly growing interest due to its potential application in spintronics devices. To successfully incorporate spin into existing semiconductor technology, one has to overcome technical difficulties such as efficient spin-polarized injection, transport, control and manipulation, as well as measurement of spin polarization. The injection of spin-polarized electrons from ferromagnetic metals into semiconductors has low efficiency, less than 1%, because of a large resistivity mismatch between ferromagnetic and semiconductor materials [1]. Rashba proposed that this problem could be solved by inserting a tunneling barrier at the metal-semiconductor interface [2].Asymmetric nonmagnetic semiconductor barriers are also used in the construction of spin filters [3]. This effect is caused by the interface-induced Rashba spin-orbit coupling [4] and can be quite significant for resonant tunneling through asymmetric double-barrier structure [5].Very recently, a multichannel field-effect spin-barrier selector was investigated theoretically utilizing the Rashba and Dresselhaus effects [6]. A considerable spin polarization and an interesting "tunneling spin-galvanic" effect were found in the tunneling of electron through a single symmetric barrier utilizing the Dresselhaus effect in the barrier [7,8]. However, the off-diagonal elements in the current operator, the contribution from the Dresselhaus effect, are neglected in these works. These off-diagonal element in the currents operator could lead to the significant correction of the spin-dependent transmission, especially in a thin barrier case.In this paper, we investigate theoretically the spin-dependent tunneling through a single symmetric barrier. The barrier and contacts consist of a zinc-blende-structure semiconductor lacking the inversion symmetry. It is shown that the spin-dependent tunneling and the electric current in the plane of the interfaces are different from the previous studies [7]. This difference is significant in thin barrier case and disappears gradually with increasing the thickness of the barrier. It is interesting to notice that the spin polarization and the interface current j are enhanced by including the Dresselhaus effect in the contact regions.We consider the transmission of an electron with initial wave vector k = (k , k z ) through a flat potential barrier of height V grown...

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Section: (2004))mentioning

confidence: 99%

Spin-dependent tunneling through a symmetric semiconductor barrier: The Dresselhaus effect

et al. 2005

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Section: Introductionmentioning

confidence: 99%

“…The development is focused on the possibility and methods of spin injection into semiconductors [4]. In order to obtain the desired spin orientation, spin-polarized carriers from magnetic materials are injected [4]. However, the conductivity mismatch of the metalsemiconductor structure is a general difficulty for electrical injection of ferromagnetic semiconductors, as reported by Schmidt et al [4][5].…”

Section: Introductionmentioning

confidence: 99%

“…In order to obtain the desired spin orientation, spin-polarized carriers from magnetic materials are injected [4]. However, the conductivity mismatch of the metalsemiconductor structure is a general difficulty for electrical injection of ferromagnetic semiconductors, as reported by Schmidt et al [4][5]. On the other hand, a spin transistor can also be achieved by using only nonmagnetic materials that exploit the unique characteristics of bulk inversion asymmetry in (110)-oriented semiconductor heterostructures, as reported by Hall et al [6][7].…”

Section: Introductionmentioning

confidence: 99%

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Transmittance and Tunneling Current through a Trapezoidal Barrier under Spin Polarization Consideration

Noor

Nabila

Mardianti

et al. 2018

J. Phys.: Conf. Ser.

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Abstract.The transmittance and tunneling current in heterostructures under spin polarization consideration were studied by employing a zinc-blended structure for the heterostructures. An electron tunnels through a potential barrier by applying a bias voltage to the barrier, which is called the trapezoidal potential barrier. In order to study the transmittance, an Airy wave function approach was employed to find the transmittance. The obtained transmittance was then utilized to compute the tunneling current by using a Gauss quadrature method. It was shown that the transmittances were asymmetric with the incident angle of the electron. It was also shown that the tunneling currents increased as the bias voltage increased.

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“…Recently, Perel' and coworkers 2 have shown that the tunneling process is itself spin dependent and, even for a symmetric heterostructure, a nonzero spin polarization can occur. In their work, tunneling through a potential barrier originating from the ⌫ conduction minimum was considered and a large spin polarization was found for the incident electron energy below the ⌫ minimum.…”

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confidence: 99%

Spin polarization via electron tunneling through an indirect-gap semiconductor barrier

2005

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We study the spin dependent tunneling of electrons through a zinc-blende semiconductor with the indirect X ͑or ⌬͒ minimum serving as the tunneling barrier. The basic difference between tunneling through the ⌫ vs the X barrier is the linear-k spin-orbit splitting of the two spin bands at the X point, as opposed to the k 3 Dresselhaus splitting at the ⌫ point. The linear coefficient of the spin splitting at the X point is computed for several semiconductors using density-functional theory and the transport characteristics are calculated using the barrier tunneling model. We show that both the transmission coefficient as well as the spin polarization can be large, suggesting the potential application of these materials as spin filters. DOI: 10.1103/PhysRevB.72.195347 PACS number͑s͒: 72.25.Ϫb, 71.20.Nr, 73.63.Ϫb An important problem in spintronics is the development of spin polarized current sources. One of the candidates for this is the asymmetric nonmagnetic heterostructure based on the interface-induced Rashba spin-orbit coupling: 1 H SO = ␣͑ ជ ϫ k ជ ͒ · n , which results in a spin-dependent potential for the scattering of the electrons ͑here, is the Pauli spin operator, k ជ is the electron momentum, n is normal to the interface, and ␣ is the coupling strength͒. The spin-dependent potential in turn leads to a net spin polarization for the outgoing electrons tunneled through the asymmetric heterostructure.Recently, Perel' and coworkers 2 have shown that the tunneling process is itself spin dependent and, even for a symmetric heterostructure, a nonzero spin polarization can occur. In their work, tunneling through a potential barrier originating from the ⌫ conduction minimum was considered and a large spin polarization was found for the incident electron energy below the ⌫ minimum. We extend the analysis to tunneling through a barrier formed by the indirect X or the ⌬ minimum. We find that both the transmission coefficient as well as the spin polarization can be large, suggesting the potential use of these materials as spin filters. The basic difference in the physics originates from the spin-orbit coupling term, viz., the k 3 Dresselhaus coupling 3 at the ⌫ point versus the linear-k coupling at the X point.We consider tunneling through a barrier ͑Fig. 1͒, where the barrier material has the zinc-blende structure with no inversion symmetry ͑e.g., AlAs͒. The basic origin of the spin polarization via tunneling lies in the spin-dependent band structure of the barrier material. If the conduction bands are spin split, then an incident electron with energy in the gap will see a spin-dependent barrier, resulting in a spindependent tunneling probability.Consider the spin splitting of the electronic band structure. Quite generally, the time-reversal symmetry demands that the energy eigenvalues of an electron in a crystal must satisfy the conditionwhere k ជ is the Bloch momentum and ↑, ↓ denote the two spin states. If, in addition, the crystal has the inversion symmetry, then the eigenvalues remain unchanged if the Bloch m...

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Spin-dependent tunneling through a symmetric semiconductor barrier

Cited by 203 publications

References 13 publications

Spin-dependent tunneling through a symmetric semiconductor barrier: The Dresselhaus effect

Spin-dependent tunneling through a symmetric semiconductor barrier: The Dresselhaus effect

Transmittance and Tunneling Current through a Trapezoidal Barrier under Spin Polarization Consideration

Spin polarization via electron tunneling through an indirect-gap semiconductor barrier

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