Interface between insulators enables information transport by spin
Modern computer technology is based on the transport of electric charge in semiconductors. But this technology’s potential will be reaching its limits in the near future, since the components deployed cannot be miniaturized further. But, there is another option: using an electron’s spin, instead of its charge, to transmit information. A team of scientists from Munich and Kyoto is now demonstrating how this works.
Computers and mobile devices continue providing ever more functionality. The basis for this surge in performance has been progressively extended miniaturization. However, there are fundamental limits to the degree of miniaturization possible, meaning that arbitrary size reductions will not be possible with semiconductor technology.
Researchers around the world are thus working on alternatives. A particularly promising approach involves so-called spin electronics. This takes advantage of the fact that electrons possess, in addition to charge, angular momentum – the spin. The experts hope to use this property to increase the information density and at the same time the functionality of future electronics.
Together with colleagues at the Kyoto University in Japan scientists at the Walther-Meißner-Institute (WMI) and the Technical University of Munich (TUM) in Garching have now demonstrated the transport of spin information at room temperature in a remarkable material system.
A unique boundary layer
In their experiment, they demonstrated the production, transport and detection of electronic spins in the boundary layer between the materials lanthanum-aluminate (LaAlO2) and strontium-titanate (SrTiO3). What makes this material system unique is that an extremely thin, electrically conducting layer forms at the interface between the two non-conducting materials: a so-called two-dimensional electron gas.
The German-Japanese team has now shown that this two-dimensional electron gas transports not only charge, but also spin. “To achieve this we first had to surmount several technical hurdles,” says Dr Hans Hübl, scientist at the Chair for Technical Physics at TUM and Deputy Director of the Walther-Meißner-Institute. “The two key questions were: How can spin be transferred to the two-dimensional electron gas and how can the transport be proven?”
Information transport via spin
The scientists solved the problem of spin transfer using a magnetic contact. Microwave radiation forces its electrons into a precession movement, analogous to the wobbling motion of a top. Just as in a top, this motion does not last forever, but rather, weakens in time – in this case by imparting its spin onto the two-dimensional electron gas.
The electron gas then transports the spin information to a non-magnetic contact located one micrometer next to the contact. The non-magnetic contact detects the spin transport by absorbing the spin, building up an electric potential in the process. Measuring this potential allowed the researchers to systematically investigate the transport of spin and demonstrate the feasibility of bridging distances up to one hundred times larger than the distance of today’s transistors.
Based on these results, the team of scientists is now researching to what extent spin electronic components with novel functionality can be implemented using this system of materials.
The research was funded by the German Research Foundation (DFG) in the context of the Cluster of Excellence “Nanosystems Initiative Munich” (NIM).
Strong evidence for d-electron spin transport at room temperature at a LaAlO3/SrTiO3 interface. R. Ohshima, Y. Ando, K. Matsuzaki, T. Susaki, M. Weiler, S. Klingler, H. Huebl, E. Shikoh, T. Shinjo, S.T.B Goennenwein and M. Shiraishi. Nature Materials, Advanced Online Publication 13. Februar 2017. DOI:10.1038/nmat4857
Dr. Hans Gregor Hübl
Magnetism, Spintronics and Nano Electromechanics
Deputy Director of Walther-Meißner-Institute, Bavarian Academy of Science,
Chair for Technical Physics (E23) at Technical University of Munich
Walther-Meißner-Straße 8, 85748 Garching, Germany
Tel.: +49 89 289 14204 – E-Mail: firstname.lastname@example.org – Web: http://www.wmi.badw.de
Dr. Isabel Leicht | idw - Informationsdienst Wissenschaft
Writing and deleting magnets with lasers
19.04.2018 | Helmholtz-Zentrum Dresden-Rossendorf
Ultrafast electron oscillation and dephasing monitored by attosecond light source
19.04.2018 | Yokohama National University
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
In an article that appears in the journal “Review of Modern Physics”, researchers at the Laboratory for Attosecond Physics (LAP) assess the current state of the field of ultrafast physics and consider its implications for future technologies.
Physicists can now control light in both time and space with hitherto unimagined precision. This is particularly true for the ability to generate ultrashort...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
19.04.2018 | Materials Sciences
19.04.2018 | Physics and Astronomy
19.04.2018 | Physics and Astronomy