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Title: X-ray-absorption near-edge structure study of IBi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub [ital y]]

Journal Article · · Physical Review, B: Condensed Matter; (United States)
 [1]; ;  [2];  [3];  [4]; ;  [3]; ;  [2];  [5]
  1. Department of Physics, Sam Houston State University, Huntsville, Texas 77341 (United States) Texas Accelerator Center, 4802 Research Forest Drive, The Woodlands, Texas 77381 (United States)
  2. Department of Physics, Rutgers University, Piscataway, New Jersey 08855 (United States)
  3. Department of Physics, Sam Houston State University, Huntsville, Texas 77341 (United States)
  4. Department of Physics, University of California at Berkeley and Material Science Division of the Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States)
  5. Department of Physics, University of California at Berkeley and Material Science Division of the Lawrence Berkeley Laboratory, Berkeley, California 947

A polarization-dependent I [ital L][sub 1-], Cu [ital K]-, and Bi [ital L][sub 3]-edge x-ray-absorption near-edge structure study has been carried out on both IBi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub [ital y]] and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub [ital y]] single crystals. The I [ital L][sub 1]-edge results indicate that the intercalated iodine layers receive electronic charges and the I 5[ital p]-orbital holes are in states primarily oriented in the I plane. The Cu [ital K]-edge results show that the electronic structure of the CuO[sub 2] layer is only slightly affected by the iodine intercalation. Some evidence for a small shift of the unoccupied Cu bands towards higher energy and a weakening of the ligand to Cu charge transfer is seen. These effects could nevertheless be contributing factors to the decrease of [ital T][sub [ital c]]. It is observed that iodine intercalation induces about 0.25 eV downward (and upward) edge shift in the Bi [ital L][sub 3]-edge spectrum with the polarization vector [bold E][ital c] axis (and [bold E][perpendicular][ital c] axis). We interpret this observation by the downward shift of the out-of-plane part and upward shift of the in-plane part of the 6[ital d][sub [ital t]2[ital g]] and 6[ital d][sub [ital e][ital g]] states, caused by the change of the Bi-O bonding configuration from octahedral to pyramidal. Our results indicate that the Bi valence state is close to +3 in both IBi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub [ital y]] and Bi[sub 2]Sr[sub 2]CaCu[sub 2]O[sub [ital y]] crystals but with the Bi sites manifesting a more metalliclike behavior along the [ital c]-axis direction upon iodine intercalation.

DOE Contract Number:
AC03-76SF00098
OSTI ID:
6901174
Journal Information:
Physical Review, B: Condensed Matter; (United States), Vol. 47:2; ISSN 0163-1829
Country of Publication:
United States
Language:
English