Magneto-optical evidence for a gapped fermi surface in underdoped YBa2Cu3O6+x.
The infrared (900-1100 cm(-1)) Faraday rotation and circular dichroism are measured in the normal state of underdoped High T(c) superconductors and used to study the magnetotransport. YBa2Cu3O6+x thin films are investigated in the temperature range 10-300 K in magnetic fields up to 8 T and as a function of oxygen concentration. A dramatic increase of the Hall frequency is observed for underdoped samples, which is not consistent with the approach to a Mott transition but is consistent with a partial gapping of the Fermi surface as predicted in density wave models.
Rigal
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Department of Physics, University of Maryland, College Park, Maryland 20742, USA.
Schmadel
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DC
Drew
H D
HD
Maiorov
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B
Osquiguil
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Preston
J S
JS
Hughes
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R
Gu
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