![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
![]() |
. | ![]() |
. |
![]() by Staff Writers Linkoping, Sweden (SPX) Jul 03, 2017
A discovery of how to control and transfer spinning electrons paves the way for novel hybrid devices that could outperform existing semiconductor electronics. In a study published in Nature Communications, researchers at Linkoping University in Sweden demonstrate how to combine a commonly used semiconductor with a topological insulator, a recently discovered state of matter with unique electrical properties. Just as the Earth spins around its own axis, so does an electron, in a clockwise or counter-clockwise direction. "Spintronics" is the name used to describe technologies that exploit both the spin and the charge of the electron. Current applications are limited, and the technology is mainly used in computer hard drives. Spintronics promises great advantages over conventional electronics, including lower power consumption and higher speed. In terms of electrical conduction, natural materials are classified into three categories: conductors, semiconductors and insulators. Researchers have recently discovered an exotic phase of matter known as "topological insulators", which is an insulator inside, but a conductor on the surface. One of the most striking properties of topological insulators is that an electron must travel in a specific direction along the surface of the material, determined by its spin direction. This property is known as "spin-momentum locking". "The surface of a topological insulator is like a well-organised divided highway for electrons, where electrons having one spin direction travel in one direction, while electrons with the opposite spin direction travel in the opposite direction. They can travel fast in their designated directions without colliding and without losing energy," says Yuqing Huang, Ph D student at the Department of Physics, Chemistry and Biology (IFM) at Linkoping University. These properties make topological insulators promising for spintronic applications. However, one key question is how to generate and manipulate the surface spin current in topological insulators. The research team behind the current study has now taken the first step towards transferring spin-oriented electrons between a topological insulator and a conventional semiconductor. They generated electrons with the same spin in gallium arsenide, GaAs, a semiconductor commonly used in electronics. To achieve this, they used circularly polarised light, in which the electric field rotates either clockwise or counter-clockwise when seen in the direction of travel of the light. The spin-polarised electrons could then be transferred from GaAs to a topological insulator, to generate a directional electric current on the surface. The researchers could control the orientation of spin of the electrons, and the direction and the strength of the electric current in the topological insulator bismuth telluride, Bi2Te3. This flexibility has according to the researchers not been available before. All of this was accomplished without applying an external electric voltage, demonstrating the potential of efficient conversion from light energy to electricity. The findings are significant for the design of novel spintronic devices that exploit the interaction of matter with light, a technology known as "opto-spintronics". "We combine the superior optical properties of GaAs with the unique electrical properties of a topological insulator. This has given us new ideas for designing opto-spintronic devices that can be used for efficient and robust information storage, exchange, processing and read-out in future information technology," says Professor Weimin Chen, who has led the study. Spin injection and helicity control of surface spin photocurrent in a three dimensional topological insulator, Y.Q. Huang, Y.X. Song, S.M. Wang, I.A. Buyanova, W.M. Chen, Nature Communications, 8, published online 22 May 2017, doi: 10.1038/ncomms15401
![]() Nashville TN (SPX) Jun 28, 2017 Building transient electronics is usually about doing something to make them stop working: blast them with light, soak them with acid, dunk them in water. Professor Leon Bellan's idea is to dissolve them with neglect: Stop applying heat, and they come apart. Using silver nanowires embedded in a polymer that dissolves in water below 32 degrees Celsius - between body and room temperatu ... read more Related Links Linkoping University Computer Chip Architecture, Technology and Manufacture Nano Technology News From SpaceMart.com
![]()
![]() |
|
The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us. |