In any computer’s hard drive, magnetic fields spin electrons this way or that. Now physicists have demonstrated that an electric field can do the same when applied to electrons in semiconductors. And unlike the older magnetic approach, their new device, called a spin gate, is capable of easily imparting a range of spin values. The team’s results, described in a report appearing today in the journal Nature, may one day help to scientists realize the ideal of spintronics—quantum computing based on electron spin states rather than charge.
David Awschalom of the University of Californa at Santa Barbara and colleagues trapped electrons in a seminconductor device made of layered gallium arsenide and aluminum gallium arsenide. By carefully adjusting the distribution of electron-transmitting aluminum across the device, they were able to create an energy barrier with sloping sides like a valley, instead of the usual box shape. When the researchers applied a voltage to the setup, the valley walls tilted like a seesaw. As electrons crossed from one material to the other through the well, quantum mechanical effects altered their spins according to how positive or negative the field was. "It’s a scalable, controllable way to manipulate the electron’s spin at the nanometer scale," Awschalom says. "Most schemes for quantum information processing require you to electrically tune the spin of the electron."
He adds that the very difficult next step would be to find a way to bind together the spin states of multiple electrons within these wells. But meeting this goal will require a lot of new physics, he says. "These devices will be a lab in which we can explore this physics."
JR Minkel | Scientific American
Non-volatile control of magnetic anisotropy through change of electric polarization
12.11.2019 | Kanazawa University
Thorium superconductivity: Scientists discover new high-temperature superconductor
11.11.2019 | Moscow Institute of Physics and Technology
If you've ever tried to put several really strong, small cube magnets right next to each other on a magnetic board, you'll know that you just can't do it. What happens is that the magnets always arrange themselves in a column sticking out vertically from the magnetic board. Moreover, it's almost impossible to join several rows of these magnets together to form a flat surface. That's because magnets are dipolar. Equal poles repel each other, with the north pole of one magnet always attaching itself to the south pole of another and vice versa. This explains why they form a column with all the magnets aligned the same way.
Now, scientists at ETH Zurich have managed to create magnetic building blocks in the shape of cubes that - for the first time ever - can be joined together to...
Quantum-based communication and computation technologies promise unprecedented applications, such as unconditionally secure communications, ultra-precise...
In two experiments performed at the free-electron laser FLASH in Hamburg a cooperation led by physicists from the Heidelberg Max Planck Institute for Nuclear physics (MPIK) demonstrated strongly-driven nonlinear interaction of ultrashort extreme-ultraviolet (XUV) laser pulses with atoms and ions. The powerful excitation of an electron pair in helium was found to compete with the ultrafast decay, which temporarily may even lead to population inversion. Resonant transitions in doubly charged neon ions were shifted in energy, and observed by XUV-XUV pump-probe transient absorption spectroscopy.
An international team led by physicists from the MPIK reports on new results for efficient two-electron excitations in helium driven by strong and ultrashort...
An international research group has observed new quantum properties on an artificial giant atom and has now published its results in the high-ranking journal Nature Physics. The quantum system under investigation apparently has a memory - a new finding that could be used to build a quantum computer.
The research group, consisting of German, Swedish and Indian scientists, has investigated an artificial quantum system and found new properties.
Researchers at the U.S. Department of Energy's (DOE) Argonne National Laboratory have reported a new mechanism to speed up the charging of lithium-ion...
05.11.2019 | Event News
30.10.2019 | Event News
02.10.2019 | Event News
12.11.2019 | Machine Engineering
12.11.2019 | Power and Electrical Engineering
12.11.2019 | Physics and Astronomy