Solving the fundamental limitations for RT spintronics - the role of interfaces in electron spin detection and injection
Lead Research Organisation:
University of Cambridge
Department Name: Physics
Abstract
Electric current in conventional semiconductor electronics is controlled by a voltage applied to various parts of any particular electronic component. However, a completely new way of controlling the flow of electric current was proposed some twenty years ago. This new idea is based on the observation that the internal angular momentum of electrons (spin) with its associated magnetic moment is conserved over nanoscale distances. It follows that, when an ultrathin layer structure is prepared, the spin 'remembers' its orientation across the whole thickness of the structure, which means that electrons with different spin orientations do not mix and flow independently as if in two separate wires connected in parallel. If the layer structures contains magnetic layers the two spin channels become inequivalent. Moreoever, it is found that the resistance of electrons with a given spin orientation depends on the magnetic configuration of all the magnetic components in the layer structure. Since the magnetic configuration can be altered by applying a magnetic field, one can control the flow of electrons (electrical current) by applying a magnetic field. With this discovery the era of an entirely new field of condensed matter physics called spintronics had began. Successful applications of the ideas of spintronics depends on our ability to grow ultrathin magnetic layer structures which are near perfect on an atomic scale. Within the last twelve months this has been achieved for layer structures containing ferromagnetic metals (FM) and MgO insulating barrier. However, for multilayers contaning FM layers and semidoncuctor (SC) layers these ideal conditions have yet to be reasloed. Yet the future success of spintronics depends on integration of spintronic components into conventional semiconductor structures. The main goal of this proposal is to combine experimental expertise in the area of classical spintronics and, in particular, expertise in epitaxial growth of layer structures with theoretical insights gained from studying near perfect magnetic junctions with an MgO barrier, We are confident that both experimental and theoretical methods developed for magnetic junctions with an MgO barrier can be transferred to FM/SC systems and thus the outstanding problem of achieving near perfect spin transport across FM/SC interfaces can be solved.
Organisations
Publications
Ando K
(2010)
Photoinduced inverse spin-Hall effect: Conversion of light-polarization information into electric voltage
in Applied Physics Letters
Ando K
(2010)
Direct conversion of light-polarization information into electric voltage using photoinduced inverse spin-Hall effect in Pt/GaAs hybrid structure: Spin photodetector
in Journal of Applied Physics
Fleet L
(2010)
Schottky Barrier Height in Fe/GaAs Films
in IEEE Transactions on Magnetics
Honda S
(2008)
Spin polarization control through resonant states in an Fe/GaAs Schottky barrier
in Physical Review B
Khalid N
(2018)
Structure and magnetic properties of an epitaxial Fe(110)/MgO(111)/GaN(0001) heterostructure
in Journal of Applied Physics
Kurebayashi H
(2010)
Numerical calculation model for spin-dependent transport of photoexcited electrons across Fe/GaAs(0 0 1) interfaces
in Journal of Physics D: Applied Physics
Kurebayashi H
(2010)
Electrical determination of the spin relaxation time of photoexcited electrons in GaAs
in Applied Physics Letters
Okamoto N
(2014)
Electric control of the spin Hall effect by intervalley transitions.
in Nature materials
Shen C
(2010)
Spin transport in germanium at room temperature
in Applied Physics Letters
Valladares L
(2014)
Surface morphology of amorphous germanium thin films following thermal outgassing of SiO 2 /Si substrates
in Applied Surface Science
Description | Spintronic devices require some means to inject electrical currents that are purely spin polarised into them. This grant enabled us to study a way of doing this that consists of passing a current through a thin film of magnetic material. We generated spin polarised carriers optically and used them to probe the interface between the magnetic material and the spintronic device in order to determine exactly how efficient spin injection can be and what quantum process are relevant to it. |
Exploitation Route | Our success enabled us to apply for a second grant: EPSRC Reference: EP/J003638/1 Title: Spintronic device physics in Si/Ge Heterostructures. |
Sectors | Other |
URL | http://www.tfm.phy.cam.ac.uk |
Description | Our research has enabled us to understand the quantum and spintronic physics of transition metal/semiconductor interfaces. |
First Year Of Impact | 2013 |
Sector | Other |
Impact Types | Societal |
Description | EPSRC IAA Knowledge Transfer Fellowship: Commissioning of a Thin Film Topological Insulator Molecular Beam Epitaxy Chamber |
Amount | £59,537 (GBP) |
Funding ID | KFZA/279 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2015 |
End | 09/2015 |
Description | EPSRC IAA Knowledge Transfer Fellowship: Thresholdless Domain Wall Motion in Magnetic Nanowires. |
Amount | £40,620 (GBP) |
Funding ID | KFZA/278 |
Organisation | Engineering and Physical Sciences Research Council (EPSRC) |
Sector | Public |
Country | United Kingdom |
Start | 01/2015 |
End | 10/2015 |