Eversus k Relations and Many Body Effects in the Model Insulating Copper OxideSr2Cu

Asymmetry of the electron spectrum in hole-doped and electron-doped cuprates

“…Our these results show that in accordance with the anomalous property of the electron spectrum in Fig. 2, the electron quasiparticles around the [π, 0] point disperse very weakly with momentum, and then the unusual flat band appears, while the Fermi energy is only slightly above this flat band, in qualitative agreement with these obtained from ARPES experimental measurements on doped cuprates 4,[11][12][13][14][15] .…”

“…Since many of the unconventional physical properties, including the relatively high SC transition temperature, have often been attributed to particular characteristics of low energy excitations determined by the electronic structure 1,4 , then a central issue to clarify the nature of the unconventional physical properties is how the electronic structure evolves with the doping concentration, From the angle-resolved photoemission spectroscopy (ARPES) measurements 4,11 , it has been shown that the electron spectral function A(k, ω) in doped cuprates is strongly momentum and doping dependent. For the hole doping, the charge carriers doped into the parent Mott insulators first enter into the k = [π/2, π/2] (in units of inverse lattice constant) point in the Brillouin zone 4,[11][12][13] , while the charge carriers are accommodated at the k = [π, 0] point in the electron-doped case 4,11,14,15 . Moreover, A(k, ω) has a flat band form as a function of energy ω for k in the vicinity of the [π, 0] point, which leads to the unusual quasiparticle dispersion around the [π, 0] point with anomalously small changes of electron energy as a function of momentum 4,[11][12][13][14][15] .…”

“…For the hole doping, the charge carriers doped into the parent Mott insulators first enter into the k = [π/2, π/2] (in units of inverse lattice constant) point in the Brillouin zone 4,[11][12][13] , while the charge carriers are accommodated at the k = [π, 0] point in the electron-doped case 4,11,14,15 . Moreover, A(k, ω) has a flat band form as a function of energy ω for k in the vicinity of the [π, 0] point, which leads to the unusual quasiparticle dispersion around the [π, 0] point with anomalously small changes of electron energy as a function of momentum 4,[11][12][13][14][15] . In particular, this flat band is just below the Fermi energy for the hole-doped cuprates, while it is located well below the Fermi energy for the electron-doped case.…”

X-Ray photoemission and electron-energy loss spectroscopic studies of Sr2CuO2Cl2

“…13 In contrast, almost no dispersion is observed along (100). The magnitude of the observed dispersion in ARPES is consistent with the extended t -J model, in which the single particle bandwidth is determined by twice the superexchange integral, J (2J of order 0.3eV).…”

“…Angle resolved photoemission studies (ARPES) of these singlet states in Sr2CuO2C12 have been published recently, and the observed dispersion of these highest lying states can be understood within the framework of an extended t-J model. 13 In the XPS spectrum, the satellite features due to the Cu 3d s final state are present between 10 and 13 eV, as in CuO. Finally, the peak at about 6eV can be assigned to C1 3p states.…”