A new field of physics seeking such advancements is
A University at Buffalo team, led by Hao Zeng, PhD, professor in the Department of Physics, worked with scientists around the world to discover a new way to split the energy levels between the valleys in a two-dimensional semiconductor.
The work is described in a study published online today (May 1, 2017) in the journal Nature Nanotechnology.
The key to Zeng's discovery is the use of a ferromagnetic compound to pull the valleys apart and keep them at different energy levels. This leads to an increase in the separation of valley energies by a factor of 10 more than the one obtained by applying an external magnetic field.
"Normally there are two valleys in these atomically thin semiconductors with exactly the same energy. These are called 'degenerate energy levels' in quantum mechanics terms. This limits our ability to control individual valleys. An external magnetic field can be used to break this degeneracy. However, the splitting is so small that you would have to go to the National High Magnetic Field Laboratories to measure a sizable energy difference. Our new approach makes the valleys more accessible and easier to control, and this could allow valleys to be useful for future information storage and processing," Zeng said.
The simplest way to understand how valleys could be used in processing data may be to think of two valleys side by side. When one valley is occupied by electrons, the switch is "on." When the other valley is occupied, the switch is "off." Zeng's work shows that the valleys can be positioned in such a way that a device can be turned "on" and "off," with a tiny amount of electricity.
Read more at: https://phys.org/news/2017-05-valleytronics-advancement-law.html#jCp
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