Crucial role of Cu¹⁺ ions and oxygen holes (peroxitons) in the high-temperature superconductivity of cuprates

Abstract

Recent spectroscopic data, especially based on electron spectroscopic measurements, have identified that the carriers in the normal state of the high-temperature superconducting cuprates are holes in the oxygen p-band rather than holes on copper in the form of Cu³⁺. We show that these oxygen holes can form a special kind of single pair (which we designate peroxitons) composed of O⁻---Cu⁺---O⁻) type species and essentially involving a resonating bond between the three sites. Bose condensation of these peroxitons as well as their effect on magnetic properties are discussed and it is shown that such oxygen holes are fundamental to the mechanism of superconductivity of the high T_c cuprates.