Why is the Cu(2) Asymmetry Parameter of NQR Spectra in HTSC so Small? *
نویسنده
چکیده
An explanation has been proposed for the unusual behaviour of the asymmetry parameter of NQR spectra of Cu(2) in layered cuprates. When holes are introduced into the plane, Zhang-Rice singlets (ZRS) appear which have a strong vibronic coupling to tetragonal and orthorhombic modes. The equation for the adiabatic potential has been derived. It is shown that its minimum, correspond ing to orthorhombic distortions of the oxygen plaquette around the Cu(2) ions, changes under doping to tetragonal character due to the singlet exchange coupling between copper and oxygen holes. A strong interaction of ZRS via the phonon field has been found.
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تاریخ انتشار 2013