TY - JOUR
T1 - Local lattice distortions and dynamics in extremely overdoped superconducting YSr2Cu2.75Mo0.25O7.54
AU - Conradson, Steven D.
AU - Geballe, Theodore H.
AU - Gauzzi, Andrea
AU - Karppinen, Maarit
AU - Jin, Changqing
AU - Baldinozzi, Gianguido
AU - Li, Wenmin
AU - Cao, Lipeng
AU - Gilioli, Edmondo
AU - Jiang, Jack M.
AU - Latimer, Matthew
AU - Mueller, Oliver
AU - Nasretdinova, Venera
PY - 2020/3/3
Y1 - 2020/3/3
N2 - A common characteristic of many “overdoped” cuprates prepared with high-pressure oxygen is Tc values ≥ 50 K that often exceed that of optimally doped parent compounds, despite O stoichiometries that place the materials at the edge or outside of the conventional boundary between superconducting and normal Fermi liquid states. X-ray absorption fine-structure (XAFS) measurements at 52 K on samples of high-pressure oxygen (HPO) YSr2Cu2.75Mo0.25O7.54, Tc = 84 K show that the Mo is in the (VI) valence in an unusually undistorted octahedral geometry with predominantly Mo neighbors that is consistent with its assigned substitution for Cu in the chain sites of the structure. Perturbations of the Cu environments are minimal, although the Cu X-ray absorption near-edge structure (XANES) differs from that in other cuprates. The primary deviation from the crystal structure is therefore nanophase separation into Mo- and Cu-enriched domains. There are, however, indications that the dynamical attributes of the structure are altered relative to YBa2Cu3O7, including a shift of the Cu-apical O two-site distribution from the chain to the plane Cu sites. Another effect that would influence Tc is the possibility of multiple bands at the Fermi surface caused by the presence of the second phase and the lowering of the Fermi level.
AB - A common characteristic of many “overdoped” cuprates prepared with high-pressure oxygen is Tc values ≥ 50 K that often exceed that of optimally doped parent compounds, despite O stoichiometries that place the materials at the edge or outside of the conventional boundary between superconducting and normal Fermi liquid states. X-ray absorption fine-structure (XAFS) measurements at 52 K on samples of high-pressure oxygen (HPO) YSr2Cu2.75Mo0.25O7.54, Tc = 84 K show that the Mo is in the (VI) valence in an unusually undistorted octahedral geometry with predominantly Mo neighbors that is consistent with its assigned substitution for Cu in the chain sites of the structure. Perturbations of the Cu environments are minimal, although the Cu X-ray absorption near-edge structure (XANES) differs from that in other cuprates. The primary deviation from the crystal structure is therefore nanophase separation into Mo- and Cu-enriched domains. There are, however, indications that the dynamical attributes of the structure are altered relative to YBa2Cu3O7, including a shift of the Cu-apical O two-site distribution from the chain to the plane Cu sites. Another effect that would influence Tc is the possibility of multiple bands at the Fermi surface caused by the presence of the second phase and the lowering of the Fermi level.
KW - Cuprates
KW - High-pressure oxygen
KW - Local structure
KW - Overdoped
UR - http://www.scopus.com/inward/record.url?scp=85081121244&partnerID=8YFLogxK
U2 - 10.1073/pnas.1918704117
DO - 10.1073/pnas.1918704117
M3 - Article
C2 - 32071213
AN - SCOPUS:85081121244
SN - 0027-8424
VL - 117
SP - 4559
EP - 4564
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 9
ER -