Evidence for two distinct energy scales in the Raman spectra of YBa2(Cu1-xNix)3O6.95.
We report electronic Raman scattering from Ni-substituted YBa2Cu3O6.95 single crystals with T(c) ranging from 92.5 to 78 K. The fully symmetrical A(1g) channel and the B(1g) channel which is sensitive to the d(x(2)-y(2)) gap maximum have been explored. The energy of the B(1g) pair-breaking peak remains constant under Ni doping while the energy of the A(1g) peak scales with T(c) ( E(A(1g))/k(B)T(c) = 5). Our data show that the A(1g) peak tracks the magnetic resonance peak observed in inelastic neutron scattering yielding a key explanation to the long-standing problem of the origin of the A(1g) peak.
Gallais
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Y
Laboratoire de Physique du Solide (UPR 5 CNRS) ESPCI, 10 rue Vauquelin, 75231 Paris, France.
Sacuto
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A
Bourges
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P
Sidis
Y
Y
Forget
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A
Colson
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D