Münster 1999 – scientific programme

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TT: Tiefe Temperaturen

TT 17: Theorie HTSL

TT 17.3: Talk

Thursday, March 25, 1999, 10:15–10:30, F2

Slave-boson theory for the 41 meV resonance in YBCO superconductors. — •Jan Brinckmann^1,2 and Patrick A. Lee¹ — ¹Massachusetts Institute of Technology, Cambridge, MA, U.S.A — ²Inst. f. Theorie d. Kondensierten Materie, Uni Karlsruhe

The evolution of the so-called “41 meV resonance” in the magnetic response of YBa₂Cu₃O_6+y cuprates is studied with slave-boson theory for the t–t′–J-model. The resonance appears as a collective spin fluctuation in the d-wave superconducting state. It is undamped at optimal doping (hole filling) due to a threshold in the excitation energies of particle–hole pairs with relative wave vector (π,π) . When hole filling is reduced, the resonance moves to lower energies and broadens. Our results compare well to inelastic neutron scattering experiments on optimally and underdoped YBCO .