High-T_{c} Superconductors with AF Order: Limitations on Spin-Fluctuation Pairing Mechanism

Abstract

The very intriguing antagonistic interplay of antiferromagnetism (AF) and superconductivity (SC), recently discovered in high-temperature superconductors, is studied in the framework of a microscopic theory. We explain the surprisingly large increase of the magnetic Bragg peak intensity $I_Q$ at $Q\sim (\pi ,\pi )$ in the magnetic field $H\ll H_{c2}$ at low temperatures $0<T\ll T_c,T_{AF}$ in $L{a}_{2-x}S{r}_{x}Cu{O}_4$. Good agreement with experimental results is found. The theory predicts large anisotropy of the relative intensity $R_Q(H)=(I_Q(H)-I_Q(0))/I_Q(0)$%, i.e. $R_Q(H\parallel c-axis)\gg R_Q(H\perp c-axis)$. The quantum (T=0) phase diagram at H=0 is constructed. The theory also predicts: (i) the magnetic field induced AF order in the SC state; (ii) small value for the spin-fluctuation coupling constant $g<(0.025-0.05)$ $eV$. The latter gives very small SC critical temperature $T_c(\ll 40$ $K)$, thus questioning the spin-fluctuation mechanism of pairing in HTS oxides.

Linguistic changes, improved readabilty, changed title

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Cited by in corpus (2)

• Bosonic Spectral Function and The Electron-Phonon Interaction in HTSC Cuprates
• ARPES kink is a "smoking gun" for the theory of high-Tc superconductors: dominance of the electron-phonon interaction with forward scattering peak