NMR, neutron scattering, and the one-band model ofLa2−xSr<

Phenomenological Model of Protected Behavior in the Pseudogap State of Underdoped Cuprate Superconductors

“…Our analysis also casts light on the issue of intrinsic spatial inhomogeneity in the pseudogap state [23,24,25]. The issue is how to reconcile the commensurate spin susceptibility peaks required by the spin liquid and the fit to the NMR data [26], with the incommensurate peaks seen in inelastic neutron scattering experiments [27]. The resolution was suggested some time ago by Slichter [28], who pointed out that if, as a result of Coulomb interaction between the holes, regions that were hole rich formed domain walls between regions in which one had nearly antiferromagnetic commensurate behavior, the two kinds of experiments were compatible.…”

NMR studies of pseudogap and electronic inhomogeneity in Bi2Sr2CaCu2OCrocker1, Dioguardi2, apRoberts-Warren3 et al. 2011Phys. Rev. B

“…47,48 The hyperfine form factor F α (q) = 2C αα cos(q x,y a/2) filters out Cu spin fluctuations at Q = (π/a, π/a) because the oxygen is located symmetrically between the two coppers. 22,36 However recent neutron scattering studies on Bi 2 Sr 2 CaCu 2 O 8+δ have confirmed the presence of incommensurate spin excitations at wavevectors Q 0 = Q. 15 In this case the F α (Q 0 ) does not vanish, and spin fluctuations should contribute to the spin lattice relaxation rate.…”

“…Since ξ ∼ a at T = T m , it is likely that short range spin fluctuations continue to exist down to T c . 37 The discrepancy between the neutron scattering and the oxygen NMR data is well known, and others have proposed several possible explanations, including (1) the presence of another band or degree of freedom associated with the holes on the oxygen orbitals, 22,33,51 (2) a second transferred hyperfine coupling to the next nearest Cu sites, 49 and (3) fluctuations of the EFG at the O site. 52 Another possibility is that the dynamical susceptibility contains two terms, one from the Fermi surface itself, and another from the incommensurate antiferromagnetic background.…”

“…1,16 Nuclear magnetic resonance (NMR) of the oxygen nuclei in the cuprates offers unique insight into the interplay of charge and spin degrees of freedom. [17][18][19][20][21][22] Unlike STM, NMR probes the bulk of the material, and both the quadrupolar moment and nuclear magnetic moment of the 17 O couple to the local charge and spin environments, respectively. 17 phases.…”

Crossover from a spin-density wave to the quantum Néel ground state

“…Simple as it looks, the HM displays a rich variety of regimes, with highly non-trivial physics. In fact, there is no consensus about the adequate low-energy effective action for small doping concentrations [7][8][9] , nor about the gross features of the phase diagram in that regime 7,10,11 .…”