Absence of superconductivity in the high-pressure polymorph of MgB2
نویسندگان
چکیده
Yanming Ma,1,2,* Yanchao Wang,1 and Artem R. Oganov2,3 1National Lab of Superhard Materials, Jilin University, Changchun 130012, People’s Republic of China 2Laboratory of Crystallography, Department of Materials, ETH Zurich, Wolfgang-Pauli-Stress 10, CH-8093 Zurich, Switzerland 3Geology Department, Moscow State University, 119992 Moscow, Russia Received 22 October 2008; revised manuscript received 8 January 2009; published 2 February 2009
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Micro - Raman scattering investigation of MgB 2 and RB 2 ( R = Al , Mn , Nb and Ti )
Phonon spectra have been investigated by micro-Raman scattering from 290 to 20K. New peaks at 500 and 674 cm appear below 250K in MgB2. These peaks are explained by the Fermi resonance, where Raman-active E2g intereacts with the overtone of E1u due to anhamonicity. Raman spectra of the isostructural RB2 (R=Al, Mn, Nb and Ti) have been also measured at 290K. The line width of E2g phonon of the s...
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