Studies of the Kosterlitz-Thouless transition in helium films

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1983

OSTI ID:7098485

Agnolet, G

The superfluid mass of two dimensional helium films with transition temperatures below 300 mK has been measured using a torsional oscillator technique. The superfluid component of these films correspond to less than one completed monolayer. For our lowest coverage the effective separation between superfluid atoms is 12 Angstrom. The jump in the superfluid mass scales with T/sub c/ as predicted by the theory of Kosterlitz and Thouless. Within the transition region, the dynamic behavior differs from the observed in films with higher transition temperatures (T/sub c/ > 1 K). In addition, the dynamic behavior does not scale in a systematic manner with coverage. Thermal conductance measurements have been made in conjunction with torsional oscillator measurements to study the transition region for a film with a transition temperature of 1.3 K. The divergence of the thermal conductance as T/sub c/ is approached from above agrees with the predicted exponential divergence of the correlation function xi/sub +/. Parameters for the equilibrium properties of the vortex system are determined from an analysis of the thermal conductance data. Equivalent parameters are also determined from the dynamic response of the film to the oscillating substrate by using the theory of Ambegaokar, Halperin, Nelson and Siggia. The two sets of parameters are found to be in relatively good agreement.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 7098485
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603 -- Materials-- Properties
640450* -- Fluid Physics-- Superfluidity
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CRITICAL TEMPERATURE
DATA
ELEMENTS
EXPERIMENTAL DATA
FILMS
FLUIDS
GASES
HELIUM
INFORMATION
MASS
NONMETALS
NUMERICAL DATA
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE GASES
SUPERFLUIDITY
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE