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Full-Text Articles in Physical Sciences and Mathematics
Sn/Ge(111) Surface Charge-Density-Wave Phase Transition, T. E. Kidd, T. Miller, M. Y. Chou, T.-C. Chiang
Sn/Ge(111) Surface Charge-Density-Wave Phase Transition, T. E. Kidd, T. Miller, M. Y. Chou, T.-C. Chiang
Faculty Publications
Angle-resolved photoemission has been utilized to study the surface electronic structure of 1/3 monolayer of Sn of Ge(111) in both the room-temperature (√3 × √3)R30° phase and the low-temprature (3 × 3) charge-density-wave phase. The results reveal a gap opening around the (3 × 3) Brillouin zone boundary, suggesting a Peierls-like transition despite the well-documented lack of Fermi nesting. A highly sensitive electronic response to doping by intrinsic surface defects is the cause for the unusual behaior, and a detailed calculation illustrates the origin of the (3 × 3) symmetry.
Masses For Galactic Beat Cepheids, Noella L. D'Cruz, Siobahn M. Morgan, Erika Böhm-Vitense
Masses For Galactic Beat Cepheids, Noella L. D'Cruz, Siobahn M. Morgan, Erika Böhm-Vitense
Faculty Publications
Accurate mass determinations for Cepheids may be used to determine the degree of excess mixing in the interiors of their main-sequence progenitors : the larger the excess mixing, the larger the luminosity of the Cepheid of a given mass, or the smaller the mass of a Cepheid with given luminosity. Dynamical masses determined recently for a few Cepheid binaries indicate excess mixing somewhat stronger than that corresponding to the convective overshoot models by Schaller et al. Beat Cepheids can be used similarly to test main-sequence mixing in stellar interiors. The period ratios for beat Cepheids depend on luminosity, heavy element …