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dc.contributor.author Dominik en_US
dc.contributor.author Mark en_US
dc.contributor.author Paul F. en_US
dc.contributor.author Raul Quesada en_US
dc.contributor.author Martin C. en_US
dc.contributor.author Denis en_US
dc.date.accessioned 2010-01-19T10:57:54Z
dc.date.available 2010-01-19T10:57:54Z
dc.date.issued 2007-06-28 en_US
dc.identifier http://dx.doi.org/10.1103/PhysRevB.75.224118 en_US
dc.identifier.citation Daisenberger , D , Wilson , M , McMillan , P F , Cabrera , R Q , Wilding , M C & Machon , D 2007 , ' High-pressure x-ray scattering and computer simulation studies of density-induced polyamorphism in silicon ' Physical Review B: Condensed Matter and Materials Physics , vol 75 , no. 22 , 224118 . , 10.1103/PhysRevB.75.224118 en_US
dc.identifier.other PURE: 143643 en_US
dc.identifier.other dspace: 2160/3997 en_US
dc.identifier.uri http://hdl.handle.net/2160/3997
dc.description.abstract A low- to high-density pressure-driven phase transition in amorphous silicon is investigated by synchrotron x-ray diffraction in the diamond anvil cell. Complementary atomistic molecular dynamics computer simulations provide insight into the underlying structural transformations and allow us to interpret the structure factors obtained from experiment. During compression the form of the scattering function S(Q) changes abruptly at 13.5 GPa, indicating significant structural rearrangement in the amorphous solid. In particular, the first peak in S(Q) shifts to larger Q values. The changes are correlated with the occurrence of a low- to high-density (LDA-HDA) polyamorphic transition observed previously using Raman scattering and electrical conductivity measurements. The data are analyzed to provide real space (pair distribution function) information. The experimental data are compared with results from molecular dynamics (MD) simulations using a modified Stillinger-Weber many-body potential energy function in order to extract structural information on the densified amorphous material. We deduce that the polyamorphic transition involves an abrupt increase in the proportion of 5- and 6-coordinate Si atoms. The overall structure of the HDA polyamorph can be related to that of the LDA form by creation of highly-coordinated "defects" within the tetrahedrally-bonded LDA network. However classical and quantum MD simulations indicate that an even higher density amorphous state might exist, based on structures that resemble the densely-packed metallic polymorphs of crystalline Si. en_US
dc.format.extent 11 en_US
dc.relation.ispartof Physical Review B: Condensed Matter and Materials Physics en_US
dc.subject RANGE ORDER en_US
dc.subject GE en_US
dc.subject PHASE-TRANSITION en_US
dc.subject MOLECULAR-DYNAMICS SIMULATIONS en_US
dc.subject GERMANIUM en_US
dc.subject POROUS SILICON en_US
dc.subject SUPERCOOLED LIQUID SILICON en_US
dc.subject DISORDERED PHASES en_US
dc.subject NEUTRON-DIFFRACTION en_US
dc.subject PURE AMORPHOUS-SILICON en_US
dc.title High-pressure x-ray scattering and computer simulation studies of density-induced polyamorphism in silicon en_US
dc.contributor.pbl Materials Research en_US
dc.contributor.pbl Institute of Mathematics & Physics (ADT) en_US


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