S.Nandakumar (Guest)
Spatial domains of Rahu and Kethu in Tunable spin Hall effect spintronic designs of infra/ultra levelsby Quantum Hall’s effect: FQH effect is the notion that electric current can be carried in chunks with just a fraction of the charge of an electron, a concept that was fully verified by later experiments. Observations of this and other phenomena in the FQH effect has brought new understanding of the ways in which many electrons can interact in a collective quantum state. In 1879 Edwin Hall reported the classic effect that bears his name: Running current through a wire perpendicular to a magnetic field causes the electrons to deflect sideways and generate a voltage across the wire's width. This "Hall voltage" increases continuously with increasing magnetic field, but a century later physicists discovered that under extreme conditions the Hall effect changes character, in what is now called the integer quantum Hall effect. With electrons trapped in a thin layer of semiconductor at low temperatures and high magnetic fields, the Hall voltage reaches a series of plateaus at precise values as the field is increased. Within these plateaus the ratio of the electric current to the Hall voltage [the Hall conductance] is an integer multiple of a conductance quantum, which is determined only by fundamental constants of nature. The pursuit of spintronics ultimately depends on our ability to steer spin currents and detect or flip their polarization The 1922 Stern-Gerlach _SG_ experiment1 first demonstrated that electron currents can be steered by the Zeeman force,F=−___•B_, caused by a spatially inhomogeneous magnetic field B_r_, where _ is the electron magnetic moment. The effect was recently observed for electrons in a semiconductor nanostructure, where the spatially inhomogeneous magnetic field was generated by a ferromagnetic layer.2 In a similarve in, the SG effect has been demonstrated for a beam of light passing through a medium where the photons morph into polaritons and experience a spatially inhomogeneous effective magnetic field.
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Replied on Tuesday, June 1, 2010 4:16 AM
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