Fermi surface and electronic homogeneity of the overdoped cuprate superconductorTl2Ba2CuO6+δas revealed

Abstract

We report a quantum oscillation study of Tl 2 Ba 2 CuO 6+␦ for two different doping levels ͑T c = 10 and 26 K͒ and determine the Fermi-surface size and topology in considerable detail. Our results show that Fermi-liquid behavior is not confined to the edge of the superconducting dome and is robust up to at least 0.3T c max . Superconductivity is found to survive up to a larger doping p c = 0.31 than in La 2−x Sr x CuO 4 . Our data imply that electronic inhomogeneity does not play a significant role in the loss of superconductivity and superfluid density in overdoped cuprates, and point toward a purely magnetic or electronic pairing mechanism.

Quantum oscillation studies of the Fermi surface of iron-pnictide superconductors

“…The alternative is to fit the data to a series of appropriate geometrical harmonics. This latter approach works well when the Fermi surface is relatively simple and only has small deviations from a sphere or a two dimensional tube and only a small number of harmonics are required (for example, SrRu 2 O 4 [27] or Tl 2 Ba 2 CuO 6+δ [28,29]). …”

Effects of charge inhomogeneities on elementary excitations inLa2−xSrxCuO4

“…We find further evidence for the mechanism proposed here from another cuprate superconductor. Quantum oscillation measurements showed that an overdoped Tl 2 Ba 2 CuO 6+d (Tl2201) has a much more homogenous chemical potential, 42 because the dopants in Tl2201 are farther from the copper oxide plane than the dopants in LSCO and BSCCO.…”

Accessing the entire overdoped regime in pristine YBa2Cu3O6+x by application of pressure

“…It has become one of the most extensively studied materials in the cuprate family, having well-identified critical points [7] and electronic orders [8][9][10][11][12]. While quantum oscillations and transport have been thoroughly studied in underdoped YBCO [13][14][15], similar measurements cannot be extended to the overdoped regime in the same material, despite having been successfully used to study the Fermi surface of a different cuprate, Tl 2 Ba 2 CuO 6+x (Tl-2201) [16,17]. This is due to the fact that chemical doping in YBCO can only achieve a maximum hole concentration of 19.4% with oxygen tuning, and up to 22% with calcium substitution [18].…”