Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 16: Solids At Low Temperature: Quantum Liquids, Bose-Einstein Condensates, Ultra-cold Atoms, ...
TT 16.8: Vortrag
Dienstag, 28. März 2006, 11:15–11:30, HSZ 105
Bilayer helium-3: a new two dimensional heavy fermion system with quantum criticality — •Michael Neumann, Jan Nyéki, Brian Cowan, and John Saunders — Dept. of Physics, Royal Holloway, Univ. of London, United Kingdom
Previous work [1] has shown how monolayer 3He adsorbed on graphite behaves as a two dimensional Mott-Hubbard system, complete with a “metal-insulator” transition. We report new results on bilayer 3He, which behaves as a two-dimensional two-band heavy fermion fluid. Evidence for this behaviour derives from extensive heat capacity and magnetisation measurements of 3He adsorbed on graphite pre-plated by a solid bilayer of 4He. The first 3He layer adsorbed on this composite substrate remains fluid up to and beyond layer promotion. However, it is observed to solidify significantly before the second 3He layer is completed. Remarkably, at fluid coverages on the verge of solidification, we observe a distinctive heat capacity and magnetisation maximum, which occurs at progressively lower temperatures as the coverage is increased. The magnetic instabilities in the fluid and the close analogies with quantum critical heavy fermion systems will be discussed in detail.
[1] Evidence for a Mott-Hubbard Transition in a Two-Dimensional 3He Fluid Monolayer, A. Casey, H. Patel, J. Nyéki, B. P. Cowan, and J. Saunders. Phys. Rev. Lett. 90, 115301 (2003)