Controlling the carrier concentration of the high-temperature superconductor Bi2Sr2CaCu2O8+delta in angle-resolved photoemission spectroscopy experiments

TitleControlling the carrier concentration of the high-temperature superconductor Bi2Sr2CaCu2O8+delta in angle-resolved photoemission spectroscopy experiments
Publication TypeJournal Article
Year of Publication2010
AuthorsPalczewski AD, Kondo T, Wen JS, Xu GZJ, Gu G, Kaminski A
Journal TitlePhysical Review B
Volume81
Pages104521
Date Published03/01
ISBN Number1098-0121
Accession NumberISI:000276248700115
Keywordsdispersion, fermi-surface, gap anisotropy, normal-state, scale, t-c
Abstract

We study the variation of the electronic properties at the surface of a high-temperature superconductor as a function of vacuum conditions in angle-resolved photoemission spectroscopy experiments. Normally, under inadequate ultrahigh vacuum (UHV) conditions the carrier concentration of Bi2Sr2CaCu2O8+delta (Bi2212) increases with time due to the absorption of oxygen from CO2/CO molecules that are prime contaminants present in UHV systems. We find that in an optimal vacuum environment at low temperatures, the surface of Bi2212 is quite stable (the carrier concentration remains constant); however at elevated temperatures the carrier concentration decreases due to the loss of oxygen atoms from the Bi-O layer. These two effects can be used to control the carrier concentration in situ. Our finding opens the possibility of studying the electronic properties of the cuprates as a function of doping across the phase diagram on the same surface of sample (i.e., with the same impurities and nondopant defects). We envision that this method could be utilized in other surface sensitive techniques such as scanning tunneling microscopy/spectroscopy.

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