21 research outputs found
Origin of the anomalous Hall Effect in overdoped n-type cuprates: current vertex corrections due to antiferromagnetic fluctuations
The anomalous magneto-transport properties in electron doped (n-type)
cuprates were investigated using Hall measurements at THz frequencies. The
complex Hall angle was measured in overdoped PrCeCuO samples (x=0.17 and 0.18) as a continuous function of
temperature above at excitation energies 5.24 and 10.5 meV. The results,
extrapolated to low temperatures, show that inelastic scattering introduces
electron-like contributions to the Hall response. First principle calculations
of the Hall angle that include current vertex corrections (CVC) induced by
electron interactions mediated by magnetic fluctuations in the Hall
conductivity reproduce the temperature, frequency, and doping dependence of the
experimental data. These results show that CVC effects are the source of the
anomalous Hall transport properties in overdoped ntype cuprates.Comment: 5 pages, 3 figure
Scaling and commensurate-incommensurate crossover for the d=2, z=2 quantum critical point of itinerant antiferromagnets
Quantum critical points exist at zero temperature, yet, experimentally their
influence seems to extend over a large part of the phase diagram of systems
such as heavy-fermion compounds and high-temperature superconductors.
Theoretically, however, it is generally not known over what range of parameters
the physics is governed by the quantum critical point. We answer this question
for the spin-density wave to fermi-liquid quantum critical point in the
two-dimensional Hubbard model. This problem is in the universality
class. We use the Two-Particle Self-Consistent approach, which is accurate from
weak to intermediate coupling, and whose critical behavior is the same as for
the self-consistent-renormalized approach of Moriya. Despite the presence of
logarithmic corrections, numerical results demonstrate that quantum critical
scaling for the static magnetic susceptibility can extend up to very high
temperatures but that the commensurate to incommensurate crossover leads to
deviations to scaling.Comment: Unchanged numerical results. It is now shown analytically that the
approach includes logarithmic corrections and that the critical behavior is
equivalent to the theory of Moriya. 6 pages, 3 figures, Late