Quantum Physics

   

Lattice Vibrations in Semiconductor

Authors: George Rajna

In analogy to the amplification of light in a laser, vibrations of a semiconductor crystal, so-called phonons, were enhanced by interaction with an electron current. [23] University of Central Florida researchers have developed a way to control the speed of light. Not only can they speed up a pulse of light and slow it down, they can also make it travel backward. [22] X-ray free-electron lasers (XFELs) produce incredibly powerful beams of light that enable unprecedented studies of the ultrafast motions of atoms in matter. [21] Using ultrashort laser pulses lasting a few picoseconds (trillionths of a second), Lawrence Livermore National Laboratory (LLNL) researchers have discovered an efficient mechanism for laser ablation (material removal) that could help pave the way to the use of lower-energy, less costly lasers in many industrial laser processing applications. [20] Engineers at Ruhr-Universität Bochum have developed a novel concept for rapid data transfer via optical fibre cables. [19] Particles can exchange their spin, and in this way spin currents can be formed in a material. [18] Researchers have shown that certain superconductors-materials that carry electrical current with zero resistance at very low temperatures-can also carry currents of 'spin'. [17] The first known superconductor in which spin-3/2 quasiparticles form Cooper pairs has been created by physicists in the US and New Zealand. [16] Now a team of researchers from the University of Maryland (UMD) Department of Physics together with collaborators has seen exotic superconductivity that relies on highly unusual electron interactions. [15] A group of researchers from institutions in Korea and the United States has determined how to employ a type of electron microscopy to cause regions within an iron-based superconductor to flip between superconducting and non-superconducting states. [14] In new research, scientists at the University of Minnesota used a first-of-its-kind device to demonstrate a way to control the direction of the photocurrent without deploying an electric voltage. [13]

Comments: 39 Pages.

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[v1] 2019-04-04 09:13:28

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