Possible Z2 phase and spin-charge separation in electron-doped cuprate superconductors
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 (HD) materials (where t'<0). The pseudogap 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 HD 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 pseudogap phase of electron-doped (ED) cuprates (if such a phase exists). The experimental situation in ED materials is also addressed.
- Publication:
-
Physical Review B
- Pub Date:
- July 2003
- DOI:
- 10.1103/PhysRevB.68.024501
- arXiv:
- arXiv:cond-mat/0302565
- Bibcode:
- 2003PhRvB..68b4501R
- Keywords:
-
- 74.20.Mn;
- 74.25.Dw;
- 74.72.Jt;
- Nonconventional mechanisms;
- Superconductivity phase diagrams;
- Other cuprates including Tl and Hg-based cuprates;
- Condensed Matter - Strongly Correlated Electrons;
- Condensed Matter - Superconductivity
- E-Print:
- 6 pages, 2 figures, RevTeX4. Homepage http://dao.mit.edu/~wen/