TY - JOUR
T1 - Intrinsic nature of thermally activated dynamical modes in α-U
T2 - Nonequilibrium mode creation by x-ray and neutron scattering
AU - Manley, Michael E.
AU - Alatas, Ahmet
AU - Trouw, Frans
AU - Leu, Bogdan M.
AU - Lynn, Jeffrey W.
AU - Chen, Ying
AU - Hults, W. Larry
PY - 2008/6/24
Y1 - 2008/6/24
N2 - Inelastic x-ray and neutron scattering were used to measure two matching lattice excitations on the [01ζ] zone boundary in α -uranium. The excitations have the same polarization and reciprocal-space structure, but one has energy consistent with the thermal activation energy of the other, indicating that it creates the mode. The implied mechanism, where a mode is created by an amplitude fluctuation that mirrors the mode itself, is consistent with an intrinsically localized mode (ILM), and this is supported by thermodynamic data. The reciprocal-space structure, however, indicates a mode that is extended along its polarization direction, [010], and yet fully localized along a perpendicular direction, [001]. An enhancement of the thermal but not electrical conductivity with mode activation also suggests that these modes are more mobile than conventional ILMs. The behavior is, however, qualitatively similar to that predicted for ILMs on two-dimensional hexagonal lattices, where in-plane localization has been shown to be extended over more than ten discrete units, and the modes can be highly mobile.
AB - Inelastic x-ray and neutron scattering were used to measure two matching lattice excitations on the [01ζ] zone boundary in α -uranium. The excitations have the same polarization and reciprocal-space structure, but one has energy consistent with the thermal activation energy of the other, indicating that it creates the mode. The implied mechanism, where a mode is created by an amplitude fluctuation that mirrors the mode itself, is consistent with an intrinsically localized mode (ILM), and this is supported by thermodynamic data. The reciprocal-space structure, however, indicates a mode that is extended along its polarization direction, [010], and yet fully localized along a perpendicular direction, [001]. An enhancement of the thermal but not electrical conductivity with mode activation also suggests that these modes are more mobile than conventional ILMs. The behavior is, however, qualitatively similar to that predicted for ILMs on two-dimensional hexagonal lattices, where in-plane localization has been shown to be extended over more than ten discrete units, and the modes can be highly mobile.
UR - http://www.scopus.com/inward/record.url?scp=46049088872&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.77.214305
DO - 10.1103/PhysRevB.77.214305
M3 - Article
AN - SCOPUS:46049088872
SN - 1098-0121
VL - 77
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
IS - 21
M1 - 214305
ER -