Change of Fermi-surface topology inBi2Sr2CaCu2O8+δwith doping

Abstract

We report the observation of a change in Fermi surface topology of Bi2Sr2CaCu2O 8+δ with doping. By collecting high statistics ARPES data from moderately and highly overdoped samples and dividing the data by the Fermi function, we answer a long standing question about the Fermi surface shape of Bi2Sr2CaCu2O 8+δ close to the (π,0) point. For moderately overdoped samples (Tc=80K) we find that both the bonding and antibonding sheets of the Fermi surface are hole-like. However for a doping level corresponding to Tc=55K we find that the antibonding sheet becomes electron-like. This change does not directly affect the critical temperature and therefore the superconductivity. However, since similar observations of the change of the topology of the Fermi surface were observed in LSCO [1,2] and Bi2Sr2Cu2O 6+δ [3], it appears to be a generic feature of hole-doped superconductors. Because of bilayer splitting, though, this doping value is considerably lower than that for the single layer materials, which again argues that it is unrelated to Tc. The Fermi surface is a fundamental property in condensed matter physics. In recent years there has been a lively debate about the shape of the Fermi surface of one of the most frequently studied high temperature superconductors -Bi 2 Sr 2 CaCu 2 O 8+δ [4,5]. Initially, the Fermi surface of this compound was determined by angle resolved photoemission spectroscopy (ARPES) to be holelike, and consistent with Luttinger's theorem [6]. Later there were reports of an electron-like Fermi surface when measurements were performed at higher photon energies [7,8]. High momentum resolution studies utilizing new generation electron analyzers re-established the hole-like shape of the Fermi surface for optimal doping [9,10]. The observation of bilayer splitting in the overdoped regime [11] provided further evidence that at least the bonding sheet of the Fermi surface is hole-like for a wide range of dopings. However, this study did not address the question of the shape of the antibonding sheet of the Fermi surface. For a long time, the answer to this question remained elusive, as the antibonding band near (π,0) is located very close to the chemical potential. It is important to determine the exact shape of the whole Fermi surface, as it potentially affects transport and collective properties. Knowledge of the band dispersion in this region of the Brillouin zone is also of great importance for theoretical calculations. In a broader scope, it was previously shown [1,3] that a change in the topology of the Fermi surface occurs in overdoped LSCO and heavily overdoped single layer Bi 2 Sr 2 CuO 6+δ , therefore this phenomenon may be a generic property of hole-doped cuprates. Here, we present high resolution ARPES data measured to a high degree of statistical accuracy, in order to determine the evolution of the Fermi surface with doping. We find that for moderately doped samples, both sheets of the Fermi surface are hole-like, while at higher doping levels the antibonding band becomes electron-like. The ...

Self-energy corrections to anisotropic Fermi surfaces

“…The analysis presented here is consistent with the measured Fermi surfaces of the cuprates 9 and qualitatively agrees with the doping evolution reported by ARPES. 4,5,9 The self-energy corrections found for the FS of Sr 2 RuO 4 , which mainly renormalize the ␥ sheet, are as well in qualitative agreement with ARPES measurements 8 and previous calculations. 54 The broad spectrum of experimental data available at this moment makes comparison between results from different techniques one of the most efficient methods to obtain information about response and correlation functions of unconventional materials.…”

“…In the hole-doped cuprates the Fermi surface ͑FS͒ topology changes with doping from hole-like to electron-like. 4,5 Recently, a change in the sign of the Hall coefficient has been reported for heavily overdoped LaSrCuO 4 . 6 The evolution of the FS in electron-doped copper-oxide superconductors with doping has been reported by angle-resolved photoemission spectroscopy ͑ARPES͒ experiments to change from electronpocket centered at the ͑ ,0͒ point of the Brillouin zone at low doping to a hole-like FS centered at ͑ , ͒ at higher doping.…”

Role of the van Hove singularity in the quantum criticality of the Hubbard model

“…58 At this filling, the topology of the Fermi surface also changes from hole-like (closed around the point k = (π, π)) to electron-like (closed around k = (0, 0)) with increasing filling (not shown) as seen in experiments. 74 The dispersion along the k y direction remains pinned near the Fermi level for a range of doping near the center of the superconducting dome, while the dispersion along the k x direction passes continuously through the Fermi level. This anisotropic motion of the flat dispersion is consistent with a van Hove peak which moves continuously through the Fermi level as shown in Fig.…”

“…Matrix element effects 75,76 , and the low precision of inverse photoemission can complicate the direct measurement of the flat dispersion resulting in the van Hove singularity, making indirect probes like the Fermi surface topology 74,77 and transport measurements more important. The van Hove singularity and the quantum critical point will also impact the transport properties of the system.…”

Fermi arcs in cuprate superconductors: Tracking the pseudogap belowTcand aboveT*

“…Inclusion of band splitting [14] will not significantly affect the following results. We take the Fermi level to be 34meV above the (π, 0) van Hove singularity (vHs) near optimal doping [13] and 96meV above the vHs in an underdoped sample with p = 0.11 [15].…”