Composite-fermion spin excitations as nu approaches 1/2: interactions in the Fermi sea.
Measurements of low-lying spin excitations by inelastic light scattering unveil a delicate balance between spin reversal and Fermi energies in the Fermi sea of composite fermions that emerges in the limit of nu --> 1/2. The interplays between these two fundamental quasiparticle interactions are uncovered in lowest spin-flip excitations in which the spin orientation and Landau level index of composite fermions change simultaneously. A collapse of the spin-flip excitation gap as nu --> 1/2 is linked to vanishing quasiparticle energy level spacings and loss of full spin polarization.
Dujovne
Irene
I
Department of Applied Physics and Applied Math, Columbia University, New York, New York 10027, USA.
Pinczuk
A
A
Kang
Moonsoo
M
Dennis
B S
BS
Pfeiffer
L N
LN
West
K W
KW