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Title: Studying Si/SiGe disordered alloys within effective mass theory.

Abstract

Abstract not provided.

Authors:
; ; ;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1429177
Report Number(s):
SAND2017-2873C
651796
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the American Physical Society March Meeting held March 13-17, 2017 in New Orleans, LA.
Country of Publication:
United States
Language:
English

Citation Formats

Gamble, John King,, Montano, Ines, Carroll, Malcolm S., and Muller, Richard P. Studying Si/SiGe disordered alloys within effective mass theory.. United States: N. p., 2017. Web.
Gamble, John King,, Montano, Ines, Carroll, Malcolm S., & Muller, Richard P. Studying Si/SiGe disordered alloys within effective mass theory.. United States.
Gamble, John King,, Montano, Ines, Carroll, Malcolm S., and Muller, Richard P. Wed . "Studying Si/SiGe disordered alloys within effective mass theory.". United States. doi:. https://www.osti.gov/servlets/purl/1429177.
@article{osti_1429177,
title = {Studying Si/SiGe disordered alloys within effective mass theory.},
author = {Gamble, John King, and Montano, Ines and Carroll, Malcolm S. and Muller, Richard P.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}

Conference:
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  • We review some of the advances in the calculation of the electronic structure and energetics of ordered and disordered alloys that hold out the possibility of obtaining, in the not-too-distant future, an ab initio theory of ordering and phase stability in alloys. In particular, we focus on the calculation of the ground state properties of Ni/sub 3/Al and discuss the competition between the L1/sub 2/ and D0/sub 22/ ordered structures. We review the ab initio concentration functional theory of ordering developed by Gyorffy and Stocks and its application to the short-range-ordered solid-solution state in Cu/sub c/Pd/sub 1-c/ alloys. Finally, wemore » review the generalized perturbation method approach to calculation of multisite interchange potentials in Ni/sub 3/Al, Pd/sub 3/V, and Al/sub 3/Ti and again discuss L1/sub 2//D0/sub 22/ competition as well as antiphase boundary energies in Ni/sub 3/Al.« less
  • We discuss methods which allow the determination of unique concentration dependent effective cluster interactions (ECI's) in substitutional alloys. These methods are based on the coherent potential approximation (CPA) and on the representation of the configuration dependent part of the disorder energy in terms of ECI's. Two schemes proposed for calculating ECI's within the CPA framework, the generalized perturbation method (GPM) and the embedded cluster method (ECM) are compared with one another and with the method proposed by Connolly and Williams, both formally and by means of calculations. It is found that the GPM and the ECM are conceptually and numericallymore » quite similar, the ECM corresponding to a complete summation of certain terms in the GPM expansion. Both these methods lead to unique values of ECI's for a large class of substitutional alloys, particularly strong-scattering alloys such as those involving transition metals. The Connolly-Williams approach, on the other hand, yields ECI's depending on the size of the cluster used in the fitting procedure, and thus to nonunique predictions of phase stability. The use of the GPM/ECM in calculating most stable ordered structures at T = 0K is illustrated in terms of Pd V and Pd Rh alloys, and the possible use of these methods in constructing alloy phase diagrams is briefly discussed. 23 refs., 9 figs., 1 tab.« less
  • A theory of the two-photon momentum density for positrons trapped in vacancies in concentrated substitutional binary alloys has been developed within the framework of the KKR-CPA method. Our ultimate objective is to obtain information regarding the local environment of vacancies in alloys by comparison of predicted momentum distributions with the results of 2D-ACAR experiments. The theory is formulated in terms of muffin-tin wavefunctions and real-space path operators for the electrons and the vacancy-trapped positron. Partial results are presented for a vacancy in pure Cu.
  • These lecture notes review the LDA-KKR-CPA method for treating the electronic structure and energetics of random alloys and the MF-CF and GPM theories of ordering and phase stability built on the LDA- KKR-CPA description of the disordered phase. Section 2 lays out the basic LDA-KKR-CPA theory of random alloys and some applications. Section 3 reviews the progress made in understanding specific ordering phenomena in binary solid solutions base on the MF-CF and GPM theories of ordering and phase stability. Examples are Fermi surface nesting, band filling, off diagonal randomness, charge transfer, size difference or local strain fluctuations, magnetic effects; inmore » each case, an attempt is made to link the ordering and the underlying electronic structure of the disordered phase. Section 4 reviews calculations of electronic structure of {beta}-phase Ni{sub c}Al{sub 1-c} alloys using a version of the LDA-KKR-CPA codes generalized to complex lattices.« less
  • Abstract not provided.