Gs. Shekhawat et al., OBSERVATION OF INTERCALATION OF EXCESS OXYGEN IN BI2SR2CACU2O8-CRYSTAL(Y SINGLE), Applied physics letters, 67(22), 1995, pp. 3343-3345
Effects arising from the intercalation of excess oxygen in Bi-O layer
has been observed at room temperature using atomic force microscopy. T
he excess oxygen is incorporated by oxygenating the pure sample. The o
xygen is trapped between the alternating Bi-O layers along the b direc
tion. This leads to a change in the local interatomic bond length alon
g the b axis, while the periodicity remained invariant along the a axi
s. In addition, in-plane atomically resolved structure of single cryst
al has been imaged at room temperature using AFM. The lattice spacings
indicate that the observed structure corresponds to the in-plane bism
uth and oxygen positions. Furthermore, high-resolution scanning tunnel
ing spectroscopy measurements show that oxygen doping increases the Bi
-O layer density of states near the Fermi level giving rise to metalli
city, whereas the pure sample reveals a semiconducting energy gap in t
he tunneling spectrum. (C) 1995 American Institute of Physics.