Bilayer 3He: A Simple Two-Dimensional Heavy-Fermion System with Quantum Criticality
Michael Neumann,
Ján Nyéki,
Brian Cowan,
John Saunders*
Two-dimensional helium-3 (
3He) provides a simple model for the
experimental investigation of the emergence of quantum complexity
in a strongly correlated Fermi system. We have observed two-dimensional,
two-band heavy-fermion behavior in bilayer films of
3He atoms
when adsorbed on the surface of graphite preplated by a solid
bilayer of
4He. Thermodynamic measurements on this system showed
that the relevant control parameter is the total density of
the
3He film. The
3He bilayer system can be driven toward a
quantum critical point at which the effective mass appears to
diverge, interband coupling vanishes, and a local-moment state
appears. It opens a new testing ground for theories of quantum
criticality in heavy-fermion materials.
* To whom correspondence should be addressed. E-mail: j.saunders{at}rhul.ac.uk
