Xhyphen;ray and ultraviolet photoelectron spectroscopies were used to investigate the microscopic changes at the Ti/Bi2Sr2CaCu2O8interface. Ti extracts oxygen out of the superconductor by disrupting vital bonds such as Cumdash;O and Bimdash;O. The adatomhyphen;induced oxygen withdrawal is explained on the basis of cationic bond lengths in the superconductor and standard bond strengths. The changes associated with Cuthinsp;2pspectra are attributed to an increase in covalency of Cumdash;O bonds, which is the consequence of a rearrangement of oxygen anions around Cu+2ions. In the early stages of the interface formation, bismuth and titanium are in a complex bonding configuration, which is evident from their binding energies. The line shape analysis of Tithinsp;2pspectra reveals that Ti is in multiple oxidation states at different stages of the evolving interface. This shows that the mobility of oxygen is an important factor which controls the overlayer growth.
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