Angle-resolved photoemission study of the ladder compoundSr14Cu24O

Abstract

Angle-resolved photoemission measurements have been performed on Sr 14 Cu 24 O 41 which consists of twoleg Cu 2 O 3 ladders and edge-sharing CuO 2 chains. The data are consistent with the existence of a dispersive band near the Fermi level which has the periodicity of the ladder sublattice. The band shows a minimum binding energy at kaϭ(2nϩ1)/2, suggesting that a Mott-Hubbard gap opens on the ladder. The experimental result shows a qualitative agreement with the t-J ladder calculation. It was also found that replacement of Sr with Ca causes a transfer of holes from the chain to the ladder. ͓S0163-1829͑97͒05137-0͔

Structural modulation, hole distribution, and hole-ordered structure of the incommensurate composite crystal(Sr2Cu2Gotoh1, Yamaguchi2, Takahashi3 et al. 2003Phys. Rev. BSelf Cite282240View full textAdd to dashboardCite

“…This is qualitatively consistent with the results from the ARPES experiment, optical conductivity measurement, and electronic structure calculation. 28,40,41 The average valence of Cu͑1͒ atom in the CuO 2 chain is about 2.6. This shows that, in the ͓Sr 2Ϫx (Ca, La, Y) x Cu 2 O 3 ͔ 0.70ϩ␦ CuO 2 series, the maximum amounts of holes are prepared in the CuO 2 chain in (Sr 2 Cu 2 O 3 ) 0.70 CuO 2 .…”

“…The angle-resolved photoemission spectroscopy ͑ARPES͒ experiment has also indicated that the Cu atom in the Cu 2 O 3 ladder is substantially undoped. 40 By neglecting the structural modulation, the elec- tronic structure calculation with local-density approximation method has obtained that the valence of Cu͑2͒ in the ladder is 1.97. 41 On the whole, these quite similar results suggest that the weak modulation developed within the ladder plane hardly affects the electronic structure of the Cu 2 O 3 ladder and prepares no holes in the Cu 2 O 3 in (Sr 2 Cu 2 O 3 ) 0.70 CuO 2 .…”

Charge-density wave formation inSr14−xCaxCuGorshunov1, Haas2, Rõõm3 et al. 2002Phys. Rev. BSelf Cite496430View full textAdd to dashboardCite

“…(c) We observe the CDW-related absorptions only along the highly conducting c axis. (d) As expected for the formation of a CDW [21], experimental indications for the charge order [16] and lattice superstructure [22] are seen in the ladders of Sr 14−x Ca x Cu 24 O 41 . The phonon spectrum shows signatures of a Brillouin zone folding below 200 K [15] which gives evidence for a lattice superstructure.…”

Optical properties of the spin-ladder compoundSr14Cu24O41Popović1, Konstantinović2, Ivanov3 et al. 2000Phys. Rev. B398511View full textAdd to dashboardCite

“…According to the structural analysis [1], the ladder sublattice is face-centeredorthorhombic (space group F mmm) with a lattice parameters a=1.1459 nm, b=1. The physical properties of Sr 14 Cu 24 O 41 have attracted a lot of attention recently [2,3,4,5,6,7,8,9,10,11,12], in connection with the rich physics associated with the S=1/2…”