3He Films as Model Strongly Correlated Fermion Systems

Journal Article · Thu Sep 07 04:00:00 EDT 2006 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.2354714· OSTI ID:20884836

Neumann, Michael; Casey, Andrew; Nyeki, Jan; Cowan, Brian; Saunders, John ^[1]

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1. Dept. of Physics, Royal Holloway University of London, Egham, Surrey, TW20 0EX (United Kingdom)

Helium films on graphite are atomically layered. This allows a wide variety of studies of strong correlations in two dimensions with density as a continuously tunable parameter. Studies of a monolayer of 3He adsorbed on graphite plated by a bi-layer of HD find a divergence of effective mass with increasing density, corresponding to a Mott-Hubbard transition between a 2D Fermi liquid and a quantum spin liquid phase. While the Fermi liquid survives in 2D, non-Fermi liquid features remain at finite T, recent theories find that this correction arises from the spin component of the backscattering amplitude. In another experiment a 3He film is grown on graphite plated by a bi-layer of 3He. The first 3He layer only solidifies in the presence of an overlayer. However in the regime in which the system comprises a 3He fluid bilayer, we observe a striking maximum in the temperature dependence of both heat capacity and magnetization. This feature is driven towards T = 0 with increasing film coverage, suggestive of a quantum critical point. Well below the maximum a linear temperature dependence of the heat capacity is recovered; the coverage dependence of the effective mass identifies a (bandwidth driven) Mott-Hubbard transition at 9.8 nm-2.

• OSTI ID: 20884836
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 850; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKSCATTERING
EFFECTIVE MASS
FERMI GAS
FERMIONS
GRAPHITE
HELIUM 3
LAYERS
LIQUIDS
MAGNETIZATION
SPECIFIC HEAT
SPIN
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 0000-0013 K
THIN FILMS