- Press Releases
In the German-Russian Collaborative Research Center CRC/Transregio 160, “Coherent manipulation of interacting spin excitations in tailored semiconductors,” physicists from TU Dortmund University, the Russian Ioffe Institute, and St. Petersburg State University are focusing on the intrinsic angular momentum of electrons in semiconductors. This quantum-mechanical property, the so-called spin, influences the magnetic characteristics of a material and can be selectively controlled by a magnetic field. One team is dedicated to the spin properties in perovskite crystal structures, which are currently receiving a lot of attention as components for efficient solar cells. The physicists have published their findings in the current issue of the renowned scientific journal Nature Communications. This contribution represents the first systematic work on the spin properties of perovskite materials.
A few years ago, it was shown that a special class of perovskite crystal structures, so-called lead halides, can convert light into electricity very well. Since the manufacturing costs are low, they could be used to produce solar cells cost-effectively. Conversely, the perovskite crystal structures exhibit intense light emission when current flows through them. Thus they could also be used to manufacture light-emitting diodes.
Their practical versatility raises hopes for further applications as well: It should be possible to use light to spatially align the spins of crystal structures of charge carriers. With that, they could be used as storage media, in both classical and quantum technology fields, that would require very little energy to operate.
To do this, the scientists need to find out more about the spin properties of these crystal structures. For that purpose, a team around Dr. Vasilii Belykh at TU Dortmund University has, for the first time ever, conducted systematic experiments to understand the spins themselves and how they interact with their environment.
A variety of possible uses
Specifically, the scientists studied CsPbBr3 perovskite crystals that were produced at ETH Zurich. The physicists observed what happens when short, intense laser pulses strike the crystal structures at low temperatures and in strong magnetic fields. Dr. Belykh and his colleagues found out, on the one hand, that the spins of the electrons in the crystals react strongly to the laser pulses. That means the spins can be influenced selectively. That alone makes the perovskite crystals interesting for possible use as a storage medium. On the other hand, they also exhibit an intense interaction with the atomic nuclei in the crystals. This interaction could be cleverly exploited to achieve significant further increases in the life span of a magnetic storage device – the information should ultimately remain reliably stored on a hard disk.
With their models, scientists of the Ioffe Institute in St. Petersburg, which collaborates with TU Dortmund University in the Collaborative Research Center, were able to provide excellent theoretical descriptions for the observations.
About the scientist
Vasilii Belykh came to Dortmund as a postdoctoral researcher in 2015, to work in the German-Russian Collaborative Research Center 160. After more than three years, he returned to Russia in the fall of 2018 and now works as a senior scientist at the P. N. Lebedev Institute of the Russian Academy of Sciences in Moscow. The close ties to Dortmund still exist, nonetheless, strengthened by mutual exchange visits.
Search and find
Location & approach
The campus of TU Dortmund University is located close to interstate junction Dortmund West, where the Sauerlandlinie A 45 (Frankfurt-Dortmund) crosses the Ruhrschnellweg B 1 / A 40. The best interstate exit to take from A 45 is "Dortmund-Eichlinghofen" (closer to Campus Süd), and from B 1 / A 40 "Dortmund-Dorstfeld" (closer to Campus Nord). Signs for the university are located at both exits. Also, there is a new exit before you pass over the B 1-bridge leading into Dortmund.
To get from Campus Nord to Campus Süd by car, there is the connection via Vogelpothsweg/Baroper Straße. We recommend you leave your car on one of the parking lots at Campus Nord and use the H-Bahn (suspended monorail system), which conveniently connects the two campuses.
TU Dortmund University has its own train station ("Dortmund Universität"). From there, suburban trains (S-Bahn) leave for Dortmund main station ("Dortmund Hauptbahnhof") and Düsseldorf main station via the "Düsseldorf Airport Train Station" (take S-Bahn number 1, which leaves every 20 or 30 minutes). The university is easily reached from Bochum, Essen, Mülheim an der Ruhr and Duisburg.
You can also take the bus or subway train from Dortmund city to the university: From Dortmund main station, you can take any train bound for the Station "Stadtgarten", usually lines U41, U45, U 47 and U49. At "Stadtgarten" you switch trains and get on line U42 towards "Hombruch". Look out for the Station "An der Palmweide". From the bus stop just across the road, busses bound for TU Dortmund University leave every ten minutes (445, 447 and 462). Another option is to take the subway routes U41, U45, U47 and U49 from Dortmund main station to the stop "Dortmund Kampstraße". From there, take U43 or U44 to the stop "Dortmund Wittener Straße". Switch to bus line 447 and get off at "Dortmund Universität S".
Dortmund Airport offers flights to several destinations in Central Europe. There are regular connections to Katowice, Kraków, London and Munich. For the approximately 20km-trip from Dortmund Airport to TU Dortmund University, you can use a shuttle bus to the railway Station "Bahnhof Holzwickede", from which trains depart to Dortmund main station (please visit Verkehrsverbund Rhein-Ruhr for more information). Normally, the fastest way is to catch a taxi at Dortmund Airport.
The H-Bahn is one of the hallmarks of TU Dortmund University. There are two stations on Campus Nord. One ("Dortmund Universität S") is directly located at the suburban train stop, which connects the university directly with the city of Dortmund and the rest of the Ruhr Area. Also from this station, there are connections to the "Technologiepark" and (via Campus Süd) Eichlinghofen. The other station is located at the dining hall at Campus Nord and offers a direct connection to Campus Süd every five minutes.