A spinning top of light

Extremely short pulses of polarized light waves are excellent for studying many different types of materials. Existing methods for producing such pulses do not always produce the desired properties. The processes that take place inside matter are extremely short-lived, and the light pulses used to study them need to be similarly short — in the range of around 100 attoseconds (billionths of a billionth of a second). In this timespan, a light wave can undergo only a few rotations, which may not be enough to provide useful information about the material.

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2D Electron Gas in Polar Semiconductor Wedges


A novel route to achieve two dimensional (2D) carrier confinement in a wedge shaped wall structure, made of a polar semiconductor, has been demonstrated theoretically. Tapering of the walls along the direction of the spontaneous polarization leads to the development of charges of equal polarity on the two inclined facades of the wall.

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A new route for spintronics

Half metallic ferromagnets (HMF) offer great opportunities in the field of spintronics. This is due to their peculiar band structure [see comparison between the density of states (DoS) of a metal, nonmagnetic semiconductor and a HMF in figures (a), (b) and (c) respectively], which gives rise to large spin polarized currents even at elevated temperatures, thereby rendering them suitable for room temperature applications.

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P .P. Singh

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