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
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29.05.2017 | University of Strathclyde
The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.
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Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
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