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Possible Z2 phase and spin-charge separation in electron doped cuprate superconductors

Tiago C. Ribeiro·Xiao-Gang Wen
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Abstract

The SU(2) slave-boson mean-field theory for the tt'J model is analyzed. The role of next-nearest-neighbor hopping t' on the phase-diagram is studied. We find a pseudogap phase in hole-doped materials (where t'<0). The pseudo-gap phase is a U(1) spin liquid (the staggered-flux phase) with a U(1) gauge interaction and no fractionalization. This agrees with experiments on hole doped samples. The same calculation also indicates that a positive t' favors a Z2 state with true spin-charge separation. The Z2 state that exists when t' > 0.5J can be a candidate for the pseudo-gap phase of electron-doped cuprates (if such a phase exists). The experimental situation in electron-doped materials is also addressed.

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Tiago C. Ribeiro, Xiao-Gang Wen. 2003-08-21. Possible Z2 phase and spin-charge separation in electron doped cuprate superconductors. https://doi.org/10.1103/physrevb.68.024501

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