Superstructural ordering and phase transitions in oxide HTSC

• Published in: Physica. C, Superconductivity Vol. 317; pp. 630 - 632
• Main Authors: Golovashkin, A.I., Anshukova, N.V., Ivanova, L.I., Rusakov, A.P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-1999
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/S0921-4534(99)00159-8

From the experimental data analysis it follows that in oxide high-temperature superconductor (HTSC) systems there is the superstructural ordering which includes both spin and charge density waves. As a result the lattice period doubles and electron spectrum reconstructs with the appearing of dielectric state. At low doping (underdoped samples) for such reconstructed spectrum the Fermi surface arises and dielectric to metal transition takes place. At the higher doping level (optimal doping) the nearly square Fermi surface in the
k
x
–
k
y
plane appears around points (±
π, ±
π). The changes of the Fermi surface with doping coincided with the experimental photospectroscopy data (ARPES). These findings explain the anomalous thermal, magnetic and other properties of the oxide HTSC.