ISSN:
1432-0630
Keywords:
78.70.Bj
;
36.10.Dr
;
71.60+z
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract We have studied two-dimensional argon and nitrogen physisorbed on grafoil by conducting positron lifetime and Doppler broadening measurements as functions of adsorbate coverage and temperature. Positron lifetime and Doppler broadening parameters show turnarounds near one-half monolayer coverages at 77 K. The s parameter of the Doppler broadening spectra measured for one-half monolayer coverages of argon and nitrogen increases with temperature across the melting phase transition. We discuss the observed coverage and temperature effects following models based on Kosterlitz-Thouless-Nelson-Halperin-Young theory of two dimensional melting and positron localization in surface defects.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00324586
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