Studies of melting, crystallization, and commensurate-incommensurate transitions in two dimensions: Third year progress report
The free expansion melting of a 2D suspension of micron-size spheres contained between parallel silica plates has been analyzed in some detail. The translational and orientational correlation functions conform with KTHNY theory prediction of a two-step melting process. The visual observations and study of the defect structures and evolution strongly suggest the process is first order with two-phase coexistence taking the place of the intermediate (hexatic) phase. On the other hand, melting of a 2.88 ..mu..m monolayer on water is in accord with KTHNY including the observation of dislocation-pair unbinding at the first transition. However, there is no evidence of the dissociation of dislocation into free disclinations at the second transition (the defect structure is much too complex here). Dynamic light scattering experiments on a 2D crystal on the surface of water yield viscous damping factors, force constants and the Lame coefficients. 2D computer simulation, in collaboration with Noel Clark's group, reveal cooperative motion along chains of particles (''snakes''). They appear to be the principal cause of diffusion near the melting point and important in the melting process. 16 refs.
- Research Organization:
- Colorado Univ., Boulder (USA)
- DOE Contract Number:
- FG02-86ER45236
- OSTI ID:
- 6677451
- Report Number(s):
- DOE/ER/45236-3; ON: DE89003253
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360602 -- Other Materials-- Structure & Phase Studies
656002* -- Condensed Matter Physics-- General Techniques in Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPUTERIZED SIMULATION
CRYSTALLIZATION
CRYSTALS
DOCUMENT TYPES
HYDROGEN COMPOUNDS
LIGHT SCATTERING
MELTING
OXYGEN COMPOUNDS
PHASE TRANSFORMATIONS
PROGRESS REPORT
RESEARCH PROGRAMS
SCATTERING
SIMULATION
STRUCTURE FACTORS
SURFACE PROPERTIES
TWO-DIMENSIONAL CALCULATIONS
WATER