Abstract
We study the role played by the substrate–helium interaction in determining whether a 4He film is fluid or solid near monolayer completion. In order to glean information concerning the possible fluid-solid transition we calculate the equation of state as well as the behavior of phonons and rotons for a high density monolayer fluid film. By analyzing the behavior of the long-wavelength excitations and the roton gap, we argue that we can infer instability in the fluid phase. We study a model Lennard-Jones two parameter potential for the substrate–helium interaction. We map out in the two-parameter space the separatrix between those weak substrates that can only support a fluid monolayer from those strong substrates that support a solid. Our approach utilizes a combination of information from both variational calculations and also correlated basis function theory to examine in detail the excitation structure in the monolayer liquid as a function of film coverage and substrate potential.
Similar content being viewed by others
References
L.W. Bruch, M.W. Cole, E. Zaremba, Physical Adsorption: Forces and Phenomena (Clarendon Press, Oxford, 1997)
J.G. Dash, Films on Solid Surfaces (Academic Press, New York, 1975)
E. Cheng, G. Ihm, M.W. Cole, J. Low Temp. Phys. 74, 519 (1989)
V. Apaja, E. Krotscheck, in Microscopic Approaches to Quantum Liquids in Confined Geometries, ed. by E. Krotscheck, J. Navarro (World Scientific, Singapore, 2002), pp. 205–268
E. Krotscheck, in Microscopic Quantum Many-Body Theories and their Applications, ed. by J. Navarro, A. Polls, Lecture Notes in Physics, vol. 510 (Springer, Heidelberg, 1998), pp. 187–250
E. Krotscheck, G.-X. Qian, W. Kohn, Phys. Rev. B 31, 4245 (1985)
B.E. Clements, E. Krotscheck, C.J. Tymczak, Phys. Rev. B 53, 12253 (1996)
V. Apaja, E. Krotscheck, M.D. Miller, J. Low Temp. Phys. 145, 369 (2006)
A.D. Jackson, B.K. Jennings, A. Lande, R.A. Smith, Phys. Rev. B 24, 105 (1981)
J. Halinen, V. Apaja, K.A. Gernoth, M. Saarela, J. Low Temp. Phys. 121, 531 (2000)
P.A. Whitlock, G.V. Chester, M.H. Kalos, Phys. Rev. B 38, 2418 (1988)