ISSN:
1572-9605
Schlagwort(e):
High-Tc superconductivity
;
thermopower
;
polaron
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Elektrotechnik, Elektronik, Nachrichtentechnik
,
Physik
Notizen:
Abstract Transport measurements distinguish the superconductive phase from the parent antiferromagnetic and the overdoped metallic phases in La2−xSrxCuO4. For small x, holes in the CuO2 sheets form non-adiabatic polarons containing, experimentally, five Cu atoms. Within a polaron, a first-order contraction of the mean Cu-O bond length collapses the Hubbard U and transfers spectral weight from the Hubbard bands to the gap between them. In the superconductive phase above Tc, condensation into a polaron liquid produces an ɛ(k) dispersion curve, and dynamic pseudo Jahn-Teller deformations within the polaron give a Seebeck enhancement with Tmax≈140 K. The polarons order pair-wise into 〈110〉 stripes alternating with parent-phase stripes; below Tc, the stripes are perfectly ordered. In the overdoped phase, the parent phase is squeezed out; the vibronic states become homogeneous.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00727420
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