TY - JOUR
T1 - Bonds, bands, charge transfer excitations and superconductivity of YBa2Cu3O7-δ
AU - Yu, Jaejun
AU - Massidda, S.
AU - Freeman, Arthur J
AU - Koeling, D. D.
PY - 1987/6/8
Y1 - 1987/6/8
N2 - The different energy dispersion and Fermi surfaces arising from the bands which dominate the electronic band structure near EF in YBa2Cu3O7-δ are presented and related to their orbital charge density distributions for the Cu2 plane and Cu1 chain arrangements thereby relating their physical and chemical descriptions. Magnetic isolation of the Y ions is found to explain the existence of high Tc superconductivity of the RBa2Cu3O7-δ compounds (where R = magnetic heavy lanthanides). A conventional phonon mechanism is found to be inadequate for obtaining high Tc. Charge transfer excitations ("excitons") of occupied Cu1-O dpπ bonding orbitals into their empty Cu1-O dpσ antibonding orbital partners result in poorly screened Cu3+-Cu4+-like charge fluctuations which induce attractive interactions (-U centers) both in the chains and to the 2D (Cu2) bands-thereby promoting the high Tc via exchange of these "excitons".
AB - The different energy dispersion and Fermi surfaces arising from the bands which dominate the electronic band structure near EF in YBa2Cu3O7-δ are presented and related to their orbital charge density distributions for the Cu2 plane and Cu1 chain arrangements thereby relating their physical and chemical descriptions. Magnetic isolation of the Y ions is found to explain the existence of high Tc superconductivity of the RBa2Cu3O7-δ compounds (where R = magnetic heavy lanthanides). A conventional phonon mechanism is found to be inadequate for obtaining high Tc. Charge transfer excitations ("excitons") of occupied Cu1-O dpπ bonding orbitals into their empty Cu1-O dpσ antibonding orbital partners result in poorly screened Cu3+-Cu4+-like charge fluctuations which induce attractive interactions (-U centers) both in the chains and to the 2D (Cu2) bands-thereby promoting the high Tc via exchange of these "excitons".
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U2 - 10.1016/0375-9601(87)90807-3
DO - 10.1016/0375-9601(87)90807-3
M3 - Article
AN - SCOPUS:0342829383
VL - 122
SP - 203
EP - 208
JO - Physics Letters, Section A: General, Atomic and Solid State Physics
JF - Physics Letters, Section A: General, Atomic and Solid State Physics
SN - 0375-9601
IS - 3-4
ER -