Two-dimensional melting of dislocation vector systems

A53 282

Surface Science 125 (1983) 282 North-Holland Publishing Company

THE DYNAMICS DIFFUSION J o h n C. T U L L Y

OF

ADSORPTION,

DESORPTION

AND

SURFACE

Bell Laboratories, Murray Hill, New Jersey 07974, USA

283

Surface Science 125 (1983) 283 North-Holland Publishing Company COMPUTER

SlMILATION

STUDIES

OF MELTING

IN TWO

DIMENSIONS J o h n D. W E E K S

Bell Laboratories, Murray Hill, New Jersey 07974, USA

284

Surface Science 125 (1983) 284 North-Holland Publishing Company

SURFACE PHASE DIAGRAMS FOR ADSORPTION: FROM MONOLAYERS TO THICK-FILM BEHAVIOR, INCLUDING WE'VI'ING, DRYING AND ROUGHENING Michael WORTIS

Physics Department, University of Illinois, Urbana, Illinois 61801, USA

Surface Science 125 (1983) 285-290 North-Holland Publishing Company TWO-DIMENSIONAL MELTING SYSTEMS

285 OF DISLOCATION

VECTOR

Y. S A I T O

lnstitut fi~r Festki~rperforschung der Kernforschungsanlage Ji~lich, D-5170 Ji~lich, Fed. Rep. of Germany Received 13 May 1982; accepted for publication 10 June 1982 Dislocation vector systems with various dislocation core energies are simulated, and the nature and the mechanism of the melting phase transition there is determined by means of the energy, specific heat, dislocation density, renormalized coupling constant, shear modulus and orientational stiffness constant as well as microscopic configurations of dislocation vectors. For a system with a large core energy the melting transition is found to be continuous, caused by the dislocation unbinding mechanism predicted by Kosterlitz-Thouless and Halperin-Nelson-Young. For a system with a small core energy, grain boundary loops are nucleated in the process of melting and the phase transition turns out to be first order. The latter agrees with most of the computer experiments on atomistic systems.