Dynamic spin susceptibility of superconducting cuprates: A microscopic theory of the magnetic resonance mode

A. A. Vladimirov; D. Ihle; N. M. Plakida

doi:10.1103/PhysRevB.83.024411

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Dynamic spin susceptibility of superconducting cuprates: A microscopic theory of the magnetic resonance mode

A. A. Vladimirov, D. Ihle, N. M. Plakida

DOI 10.1103/PhysRevB.83.024411 · Physical Review B

T1

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Abstract

A microscopic theory of the dynamic spin susceptibility (DSS) in the superconducting state within the t-J model is presented. It is based on an exact representation for the DSS obtained by applying the Mori-type projection technique for the relaxation function in terms of Hubbard operators. The static spin susceptibility is evaluated by a sum-rule-conserving generalized mean-field approximation, while the self-energy is calculated in the mode-coupling approximation. The spectrum of spin excitations is studied in a homogeneous phase of the underdoped and optimally doped regions. The DSS reveals a resonance mode (RM) at the antiferromagnetic wave vector Q=π(1,1) at low temperatures due to a strong suppression of the damping of spin excitations. This is explained by an involvement of spin excitations in the decay process in addition to the particle-hole continuum usually considered in random-phase-type approximations. The spin gap in the spin-excitation spectrum at Q plays a dominant role in limiting the decay in comparison with the superconducting gap, which results in the observation of the RM even above Tc in the underdoped region. A good agreement with inelastic neutron-scattering experiments on the RM in YBa2Cu3Oy compounds is found.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
YBa2Cu3O6.5 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	59	Pressure not reported	unknown
YBa2Cu3O6.6 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	61	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	38.5	Pressure not reported	unknown
La2-xSrxCuO4 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	22	Pressure not reported	unknown