Two-dimensional quantum solid phases of adsorbed monolayers

Journal Article · Tue Jul 01 04:00:00 EDT 1975 · Sov. J. Low Temp. Phys. (Engl. Transl.); (United States)

OSTI ID:7323194

Dash, J G

Monolayer films of helium and other gases adsorbed on basal plane surfaces of graphite exhibit phenomena that indicate numerous phases and phase transitions. He/sup 3/ and He/sup 4/ at high coverages form two-dimensional quantum solids whose structures are incommensurate with the underlying graphite, contrasting sharply with the (..sqrt..3 x ..sqrt..3) epitaxial ordered lattice solids occurring at lower coverage. The 2D solid phases melt in a continuous manner, while the lattice solids show a logarithmic second-order heat capacity peak. No monolayer displays a first-order melting transition indicated by a very high and narrow anomaly. This sharp melting point may be related to partial registry between the structure of the monolayer and that of the substrate. In N/sub 2/ there is an apparent coupling between melting of the 2D type and the disordering of the lattice solid, with promotion of atoms to the second layer. Experimental methods include calorimetry, nuclear magnetic resonance, vapor pressure, and neutron diffraction. (AIP)

• Research Organization: Brookhaven National Laboratory, Upton, N.Y. 11973
• OSTI ID: 7323194
• Journal Information: Sov. J. Low Temp. Phys. (Engl. Transl.); (United States), Journal Name: Sov. J. Low Temp. Phys. (Engl. Transl.); (United States) Vol. 1:7; ISSN SJLPD
• Country of Publication: United States
• Language: English

Related Subjects

656000* -- Condensed Matter Physics
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ADSORPTION
CRYSTALS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
HELIUM 3
HELIUM 4
HELIUM ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
NUCLEAR MAGNETIC RESONANCE
NUCLEI
PHYSICAL PROPERTIES
QUANTUM CRYSTALS
RESONANCE
SORPTION
SPECIFIC HEAT
STABLE ISOTOPES
THERMODYNAMIC PROPERTIES