Researchers learn to control electron spin at room temperature to make devices more efficient and faster


Spintronics may continue down that path as our gadgets get smaller, quicker, more energy-efficient, and able to store more data. Spintronics is based on the spin of electrons, as opposed to electronics, which is based on the flow of electrons.

Because an electron has a spin degree of freedom, it may operate as a little magnet in addition to holding a charge. Using an electric field to regulate electron spin and rotate the magnet's north pole in any direction is a crucial challenge in spintronics.

The so-called Rashba or Dresselhaus spin-orbit coupling phenomenon, which proposes that one may regulate electron spin by electric field, is used by the spintronic field effect transistor. Before the technology realizes its full, tiny but potent, and environmentally friendly potential, some obstacles must be solved, notwithstanding the method's promise for efficient and high-speed computing.

Scientists have been seeking to regulate spin at room temperature using electric fields for decades, but successful control has proven elusive. A research team lead by Jian Shi and Ravishankar Sundararaman of Rensselaer Polytechnic Institute and Yuan Ping of the University of California at Santa Cruz made progress in resolving the conundrum in recent study published in Nature Photonics.

Dr. Shi, an associate professor of materials science and engineering, said that in order to have the electron spin precess fast, you need a strong Rashba or Dresselhaus magnetic field. "If it is weak, the electron spin precesses slowly and switching on or off the spin transistor would take too long. However, a greater internal magnetic field frequently results in poor control of electron spin if it is not structured properly."

A ferroelectric van der Waals layered perovskite crystal with a distinctive crystal symmetry and high spin-orbit coupling was shown to be a suitable model material for understanding Rashba-Dresselhaus spin mechanics at room temperature by the researchers. Its nonvolatile and reprogrammable room-temperature optoelectronic features connected to spin may serve as an inspiration for the creation of crucial design concepts for a room-temperature spin field effect transistor.

Dr. Sundararaman, an associate professor of materials science and engineering, claims that simulations showed this material to be especially intriguing. "The spins revolve predictably and in perfect cooperation," he stated. "The internal magnetic field is simultaneously massive and properly dispersed in a single direction." This is a crucial prerequisite for using spins for information transmission that is reliable.

According to Dr. Shi, "it's a step toward the practical implementation of a spintronic transistor."

Graduate student Christian Multunas from Dr. Sundararaman's group, postdoctoral associate Jie Jiang, and graduate student Lifu Zhang from Dr. Shi's group are the initial authors of this study.

The Physical Properties of Materials program under Dr. Pani Varanasi, the Air Force Office of Scientific Research, and the National Science Foundation all provided funding for this project.

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