YBa sub 2 Cu sub 3 O sub 7 minus x (001) studied at 60 K with momentum-resolved inverse photoemission

• Published in: Physical review. B, Condensed matter Vol. 42:1
• Main Authors: Wagener, T.J., Hu, Y., Jost, M.B., Weaver, J.H.
• Format: Journal Article
• Language: English
• Published: United States 01-07-1990
• Subjects: 360204 - Ceramics, Cermets, & Refractories- Physical Properties; ALKALINE EARTH METAL COMPOUNDS; BAND THEORY; BARIUM COMPOUNDS; BARIUM OXIDES; CHALCOGENIDES; COPPER COMPOUNDS; COPPER OXIDES; ELECTRONIC STRUCTURE; EMISSION; HIGH-TC SUPERCONDUCTORS; MATERIALS SCIENCE; OXIDES; OXYGEN COMPOUNDS; PHOTON EMISSION; SUPERCONDUCTORS; TRANSITION ELEMENT COMPOUNDS; VERY LOW TEMPERATURE; YTTRIUM COMPOUNDS; YTTRIUM OXIDES
• ISSN: 0163-1829; 1095-3795
• DOI: 10.1103/PhysRevB.42.1041

Momentum-resolved inverse photoelectron spectroscopy has been used to study the unoccupied electronic states of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} (001) at 60 K. We find low emission between {ital E}{sub {ital F}} and {ital E}{sub {ital F}}+2 eV that is attributed to empty Cu 3{ital d}--O 2{ital p} hybrids and structure at {similar to}7, 9, and 14 eV above {ital E}{sub {ital F}} that results from the Ba 5{ital d}, Y 4{ital d}, and Ba 4{ital f} levels, respectively. An O 2{ital p} hole-derived feature centered at {ital E}{sub {ital F}}+1 eV is observed to resonate when the incident electron energy is {similar to}18 eV. Normal incidence studies show nondispersive empty-state features at {ital E}{sub {ital F}}+0.5, 1, 1.8, and 3 eV. Angle-dependent studies that probe along {Gamma}-{ital Y} show dispersion with two bands derived from the Cu-O chains reaching a maximum at {ital Y} ({ital E}{sub {ital F}}+0.4 and 1.5 eV). These off-normal results are consistent with angle-resolved photoemission studies of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} (001) and are discussed within the context of band-structure calculations.