Tunable spin-tunnel contacts to silicon using low-work-function ferromagnets

Min, Byoung‐Chul; Motohashi, K.; Lodder, Cock; Jansen, R.

doi:10.1038/nmat1736

Cited by 181 publications

(141 citation statements)

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“…Recently, methods for spin injection and/or detection in silicon (Si) were explored intensely [2,3,4,5,6,7] because Si has a long spin relaxation time and is compatible with the current industrial semiconductor technologies. Although electrical detections of spin transport in Si conduction channels were demonstrated by two research groups, [4,5] an insulating Al 2 O 3 tunnel barrier between FM and Si was utilized for efficient spin injection and/or detection.…”

Section: Pacs Numbersmentioning

confidence: 99%

Electrical injection and detection of spin-polarized electrons in silicon through an Fe3Si/Si Schottky tunnel barrier

Ando

Hamaya

Kasahara

et al. 2009

Applied Physics Letters

133

112

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We demonstrate electrical injection and detection of spin-polarized electrons in silicon (Si) using epitaxially grown Fe3Si/Si Schottky-tunnel-barrier contacts. By an insertion of a δ-doped n + -Si layer (∼ 10 19 cm −3 ) near the interface between a ferromagnetic Fe3Si contact and a Si channel (∼ 10 15 cm −3 ), we achieve a marked enhancement in the tunnel conductance for reverse-bias characteristics of the Fe3Si/Si Schottky diodes. Using laterally fabricated four-probe geometries with the modified Fe3Si/Si contacts, we detect nonlocal output signals which originate from the spin accumulation in a Si channel at low temperatures. PACS numbers:To solve critical issues caused by the scaling limit of complementary metal-oxide-semiconductor (CMOS) technologies, spin-based electronics (spintronics) has been studied.[1] For semiconductor spintronic applications, an electrical spin injection from a ferromagnet (FM) into a semiconductor (SC) and its detection are crucial techniques.Recently, methods for spin injection and/or detection in silicon (Si) were explored intensely [2,3,4,5,6,7] because Si has a long spin relaxation time and is compatible with the current industrial semiconductor technologies. Although electrical detections of spin transport in Si conduction channels were demonstrated by two research groups, [4,5] an insulating Al 2 O 3 tunnel barrier between FM and Si was utilized for efficient spin injection and/or detection. To realize gate-tunable spin devices, e.g., spin metal-oxidesemiconductor field effect transistors (spin MOSFET), [8] demonstrations of electrical spin injection and detection in Si conduction channels using Schottky tunnel-barrier contacts will become considerably important. [9,10] By low-temperature molecular beam epitaxy (LTMBE), we recently demonstrated highly epitaxial growth of a binary Heusler alloy Fe 3 Si on Si and obtained an atomically abrupt heterointerface. [11] In this letter, inserting a heavily doped n + -Si layer near the abrupt interface between Fe 3 Si and n-Si, we achieve an effective Shottky tunnel barrier for spin injection into Si. Using nonlocal signal measurements, we demonstrate electrical injection and detection of spin-polarized electrons in Si conduction channels though the Schottky-tunnel-barrier contacts.The n + -Si layer was formed on n-Si(111) (n ∼ 4.5 × 10 15 cm −3 ) by a combination of the Si solid-phase epitaxy with an Sb δ-doping process, [12] where the carrier * E-mail: hamaya@ed.kyushu-u.ac.jp † E-mail: miyao@ed.kyushu-u.ac.jp concentration of the n + -Si layer was ∼ 2.3 × 10 19 cm −3 , determined by Hall effect measurements, and ∼ 10-nmthick non-doped Si layer was grown on the Sb δ-doped layer. Ferromagnetic Fe 3 Si layers with a thickness of ∼ 50 nm were grown by LTMBE at 130 • C, as shown in our previous work.[11] The interface between Fe 3 Si and n + -Si was comparable to that shown in Ref. 11. To evaluate electrical properties of the Fe 3 Si/Si Schottky contacts, we firstly fabricated two different Schottky diodes (∼ 1 mm in diameter) with and w...

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Section: Pacs Numbersmentioning

confidence: 99%

Electrical injection and detection of spin-polarized electrons in silicon through an Fe3Si/Si Schottky tunnel barrier

Ando

Hamaya

Kasahara

et al. 2009

Applied Physics Letters

133

112

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“…Spin injection into silicon was first achieved in 2006, using tunnel contacts with an Al 2 O 3 barrier [7]. In 2009, room temperature spin injection was achieved in heavily n-and p-doped silicon [8].…”

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confidence: 99%

Strained germanium for applications in spintronics

Morrison

Myronov

2016

Physica Status Solidi (a)

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Germanium (Ge) is another group-IV semiconductor material, which recently started attracting tremendous attention in spintronics following success of silicon (Si). The crystal inversion symmetry of Si and Ge precludes the spin relaxation of conduction electrons by the Dyakonov-Perel mechanism, resulting in a long spin relaxation time. Since the proposal of the spin FET in 1990 by Datta and Das, semiconductor materials have been studied for their spin-orbit (S-O) interactions, particularly those that can be modified by an applied electric field, such as the Rashba S-O interaction, in order to create devices that utilise spin modulation and control to perform logic operations. Since then new proposals have appeared. Nowadays they include spin transistors with several different operating principles, spin-based diodes, spin-based field programmable gate arrays, dynamic spin-logic circuits, spin-only logic, spin communication and others. In this review, the focus will be made on presenting recent progress in Ge spintronics including the key advances made. The absence of Dresselhaus S-O coupling in Ge enables a longer spin diffusion length when compared to III-V semiconductor materials. Evidence of a strong Rashba S-O interaction in strained Ge quantum wells has begun to emerge. Also, the first experimental demonstration of room-temperature spin transport in Ge has recently been reported.

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“…proper choice of the material for the non-magnetic electrode [32], this device could be invaluable for achieving controllable spin injection.…”

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confidence: 99%

Electrically Tunable Spin Polarization in a Carbon Nanotube Spin Diode

Merchant

Marković

2008

Phys. Rev. Lett.

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We have studied the current through a carbon nanotube quantum dot with one ferromagnetic and one normal-metal lead. For the values of gate voltage at which the normal lead is resonant with the single available non-degenerate energy level on the dot, we observe a pronounced decrease in the current for one bias direction.We show that this rectification is spin-dependent, and that it stems from the interplay between the spin accumulation and the Coulomb blockade on the quantum dot. Our results imply that the current is spin-polarized for one direction of the bias, and that the degree of spin polarization is fully and precisely tunable using the gate and bias voltages. As the operation of this spin diode does not require high magnetic fields or optics, it could be used as a building block for electrically controlled spintronic devices.The ability to create, manipulate and detect spin currents is central to the development of spintronic devices [1]. Controlling the spin currents by purely electrical means [2,3] is particularly interesting, as that would allow the integration of spintronic

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Tunable spin-tunnel contacts to silicon using low-work-function ferromagnets

Cited by 181 publications

References 35 publications

Electrical injection and detection of spin-polarized electrons in silicon through an Fe3Si/Si Schottky tunnel barrier

Electrical injection and detection of spin-polarized electrons in silicon through an Fe3Si/Si Schottky tunnel barrier

Strained germanium for applications in spintronics

Electrically Tunable Spin Polarization in a Carbon Nanotube Spin Diode

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