Strong suppression of the kosterlitz-thouless transition in a He4 film under high pressure

We have found that the surface specularity for He3 quasiparticle scattering is closely related to the superfluidity and the Kosterlitz-Thouless (KT) transition of He4 film adsorbed on the surface. The specularity is determined by measurements of the transverse acoustic impedance of bulk liquid He3. The unique point of our system is that we can control the correlation among He4 atoms in the film by changing the pressure of the bulk He3. The observed KT transition temperature is significantly suppressed by increasing the pressure, which suggests a strong correlation effect on KT transition.