The research team has succeeded in generating and detecting back currents in graphene, not using any external magnetic fields for the first time, successfully solving a long -term challenge in physics. Development could play an important role in the development of the next generation of quantum devices.
Special rotation currents are the main ingredient in Spintronics, a new type of technology that is used by electron rotation, not electric charge. Spintronics promises extremely large, especially efficient energy -efficient devices than today’s electronics, but forced to operate in practical material such as graphene.
“First of all, to detect quantum rotation currents in graphene, there was always large magnetic fields that are virtually impossible to integrate into the chip,” said Talieh Gh, the main researcher at the Delft University of Technology (TU Delft).
However, in the latest study, his team now showed that by placing a graphene on a carefully selected magnetic material, they can activate and control quantum rotation currents without magnets. This discovery could prepare the way especially to Spin circuits and help fill the gap between electronics and future quantum technology.
Achieving the Double Hall Effect in Grafen
To understand what this study is special, it is important to know that the team has tried to create the Quantum Spin Hall (QSH) effect. This is a special state where electrons move only along the edges of the material and their spins direct in the same direction.
The movement is smooth and does not fall due to small flaws, which is a dream scenario for the production of efficient, low -power chains. But so far, Graphen’s showing had to be adapted to strong magnetic fields.
Instead of forcing the graphene to deal with magnets differently, the researchers chose a different approach. On layered magnetic material called chrome thiophosphate (CRPS₄), they put a leaf of graphene. This material naturally affects nearby electricians through what scientists call the magnetic closeness effect.
An unexpected anomalized hall effect
When graphene is stacked on CRPS₄, its electrons begin to feel two main forces; The spin-correction (which links the electron movement to its rotation) and the exchange interaction (which promotes certain directions of rotation). These forces have opened the energy gap in the graphene structure and causes the onset of conductive states, which is a sign of QSH effect.
Researchers confirmed that the back currents flow along the edges of the graphene and remained stable dozens of micrometers, even in small defects.
They also noticed something unexpected, anomalous hall (AH) effect when electrons are directed to the side, even without an external magnetic field. Unlike the QSH effect they noticed at low (cryogenic) temperatures, this anomali behavior remained even at room temperature.
“The detection of QSH states in the zero external magnetic field, along with the AH signal that persists to room temperature, opens the way to the practical application of magnetic graphene in quantone spint -based circuits,” the study authors notes.
Huge potential of spin currents
Stable, topologically protected rotation currents could be used to transmit quantum information over larger distances, possibly connecting quarters on future quantum computers. They also open the door to especially memory and logical circuits that operate cooler and more efficient than today’s silicon -based devices.
“These topologically protected rotation currents are strong from disorders and defects, so they are reliable even under imperfect conditions,” GHAI said.
However, there are still a few restrictions to overcome. Unlike AH, the QSH effect, which is more suitable for creating quantum chains, is only noticeable here at very low temperatures, which limits its direct use in electronics.
Researchers are now seeking to investigate ways to impact at higher temperatures and to investigate other combinations of materials in which this approach can work.
The study was published in the magazine Nature relationships;