Muñoz, J. A. and Lucas, M. S. and Mauger, L. and Halevy, I. and Horwath, J. and Semiatin, S. L. and Xiao, Yuming and Chow, Paul and Stone, M. B. and Abernathy, D. L. and Fultz, B. (2013) Electronic structure and vibrational entropies of fcc Au-Fe alloys. Physical Review B, 87 (1). Art. No. 014301. ISSN 1098-0121 http://resolver.caltech.edu/CaltechAUTHORS:20130211-115651354
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Phonon density of states (DOS) curves were measured on alloys of face-centered-cubic (fcc) Au-Fe using nuclear resonant inelastic x-ray scattering (NRIXS) and inelastic neutron scattering (INS). The NRIXS and INS results were combined to obtain the total phonon DOS and the partial phonon DOS curves of Au and Fe atoms from which vibrational entropies were calculated. The main effect on the vibrational entropy of alloying comes from a stiffening of the Au partial phonon DOS with Fe concentration. Force constants were calculated from first principles for several compositions and show a local stiffening of Au-Au bonds close to Fe atoms. The calculated phonon DOS curves reproduce the experimental trend. The stiffening is attributed to two main effects comparable in magnitude: (i) an increase in electron density in the free-electron-like states and (ii) stronger sd hybridization.
|Additional Information:||© 2013 American Physical Society. Received 13 September 2012; revised 12 November 2012; published 10 January 2013. Portions of this work were performed at HPCAT (Sector 16), Advanced Photon Source (APS), Argonne National Laboratory. HPCAT is supported by CIW, CDAC, UNLV, and LLNL through funding from DOE-NNSA, DOE-BES, and NSF. Use of the APS was supported by DOE-BES, under Contract No. DE-AC02-06CH11357. A portion of this research at Oak Ridge National Laboratory’s Spallation Neutron Source was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, US Department of Energy. This work benefited from DANSE software developed under NSF Grant No. DMR-0520547. This work was supported by DOE BES under contract DE-FG02-03ER46055.|
|Classification Code:||PACS: 63.20.dd, 63.20.Pw, 71.20.Be, 75.50.Bb|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||12 Feb 2013 00:46|
|Last Modified:||12 Feb 2013 00:46|
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