Abstract
A recent study of the transport properties on the stripe phase in La1.875Ba01.25CuO4 by Li et al (2007 Phys. Rev. Lett. 99 067001) found two-dimensional (2D) superconductivity over a wide temperature range including a Berezinski–Kosterlitz–Thouless transition at a temperature T=16 K, with 3D superconducting (SC) ordering only at T=4 K. These results contradict the long standing belief that the onset of superconductivity is suppressed by stripe ordering and suggest coexistence of stripe and SC phases. The lack of 3D SC order above T=4 K requires an antiphase ordering in the SC state to suppress the interlayer Josephson coupling as proposed by Berg et al (2007 Phys. Rev. Lett. 99 127003). Here, we use a renormalized mean field theory for a generalized t–J model to examine in detail the energetics of the spin and charge stripe ordered SC states including possible antiphase domains in the SC order. We find that the energies of these modulated states are very close to each other and that the anisotropy present in the low temperature tetragonal crystal structure favors stripe resonating valence bond states. The stripe antiphase SC states are found to have energies very close to, but always above, the ground state energy, which suggests additional physical effects are responsible for their stability.
Highlights
In this paper, we report on calculations using the renormalized mean field theory (RMFT) method to examine in greater detail the energetics of these novel modulated states within the generalized t − t − t − J model
We report on calculations using the RMFT method to examine in greater detail the energetics of these novel modulated states within the generalized t − t − t − J model
The local density of states (LDOS) that appears in figure 7(d) shows clearly an enhanced density of states (DOS) near zero energy which implies a substantial energy cost to introduce the π DW into a uniform dSC state
Summary
The t–J model was introduced in the early days of cuprate research by Anderson and by Zhang and Rice to describe lightly hole doped CuO2 planes [11]. G(ti, j),σ t(i, j) ci†,σ cj,σ + h.c. The renormalization factors gt , g s,xy and g s,z used to evaluate a projected mean field wavefunction depend on the local values of the magnetic and pairing order parameters and the local kinetic energy and hole density which are defined as follows: mi = 0| Siz | 0 , i, j ,σ = σ 0| ci,σ cj,−σ | 0 , (3). ∂W ∂O g in the above equations refer to the derivative of W with respect to the mean field O via the Gutzwiller g-factors (see equation (4)) This mean field Hamiltonian HMF in equation (8) is solved self-consistently. We always diagonalize HMF for a sample consisting of 257 supercells along the direction with periodic boundary condition unless stated explicitly otherwise
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