118 research outputs found

    Sign changes and resonance of intrinsic spin Hall effect in two-dimensional hole gas

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    The intrinsic spin Hall conductance shows rich sign changes by applying a perpendicular magnetic field in a two-dimensional hole gas. Especially, a notable sign changes can be achieved by adjusting the characteristic length of the Rashba coupling and hole density at moderate magnetic fields. This sign issue may be easily realized in experiments. The oscillations of the intrinsic spin Hall conductance as a function of 1/BB is nothing else but Shubnikov-de Haas oscillations, and the additional beatings can be quantitatively related to the value of the spin-orbit coupling parameter. The Zeeman splitting is too small to introduce effective degeneracy between different Landau levels in a two-dimensional hole gas, and the resonant intrinsic spin Hall conductance appears in high hole density and strong magnetic field due to the transition between mostly spin-1/2-{1/2} holes and spin-3/2 holes is confirmed. Two likely ways to establish intrinsic spin Hall effect in experiments and a possible application are suggested.Comment: Accepted for publication in Applied Physics Letters, an enlarged version, 5 pages, 4 fig

    Unusual charge transport and spin response of doped bilayer triangular antiferromagnets

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    Within the t-J model, the charge transport and spin response of the doped bilayer triangular antiferromagnet are studied by considering the bilayer interaction. Although the bilayer interaction leads to the band splitting in the electronic structure, the qualitative behaviors of the physical properties are the same as in the single layer case. The conductivity spectrum shows the low-energy peak and unusual midinfrared band, the temperature dependent resistivity is characterized by the nonlinearity metallic-like behavior in the higher temperature range, and the deviation from the metallic-like behavior in the lower temperature range, and the commensurate neutron scattering peak near the half-filling is split into six incommensurate peaks in the underdoped regime, with the incommensurability increases with the hole concentration at lower dopings, and saturates at higher dopings.Comment: 8 pages, Revtex, five figures are include

    A gauge invariant dressed holon and spinon description of the normal-state of underdoped cuprates

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    A partial charge-spin separation fermion-spin theory is developed to study the normal-state properties of the underdoped cuprates. In this approach, the physical electron is decoupled as a gauge invariant dressed holon and spinon, with the dressed holon behaving like a spinful fermion, and represents the charge degree of freedom together with the phase part of the spin degree of freedom, while the dressed spinon is a hard-core boson, and representing the amplitude part of the spin degree of freedom. The electron local constraint for single occupancy is satisfied. Within this approach, the charge and spin dynamics of the underdoped cuprates are studied based on the t-t'-J model. It is shown that the charge dynamics is mainly governed by the scattering from the dressed holons due to the dressed spinon fluctuation, while the scattering from the dressed spinons due to the dressed holon fluctuation dominates the spin dynamics.Comment: 10 pages, 7 figures, corrected typo

    Ground state pairing correlations in the S4S_4 symmetric microscopic model for iron-based superconductors

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    We present the ground state pairing correlations in the S4S_4 symmetric microscopic model for iron-based superconductors, computed with the constrained-path Monte Carlo method. For various electron fillings and interaction strengths, we find that the sxys_{xy} pairing dominates over other pairing correlations and is positive when the pair separation exceeds several lattice constants, whatever for iron pnictides and iron chlcogenides. These ground state properties, especially the long range part pairing correlations re-confirm the previous finite temperature results published in Phys. Rev. Lett. 110, 107002(2013). We further our study by including the nearest neighbour interaction VV and it is found that the sxys_{xy} pairing correlation is slightly suppressed by the increasing VV.Comment: 5 pages, 5 figures. arXiv admin note: text overlap with arXiv:1202.5881 by other author