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The recent experiments by Li et al [ 1 ] have overturned the standard view of the stripe phase in the underdoped cuprates as simple SDW states with a CDW harmonic which suppress superconductivity. Their results on La1.875Ba0.125CuO4 show that a transition into a SDW state accompanied by 2D superconductivity occurs below the transition into the LTT phase which itself displays CDW ordering. Berg et al [ 2 ] argue persuasively the 2D character of the superconductivity requires that each plane contains an array of ð-phase shift domain walls thereby suppressing interplanar Josephson coupling. The possibility of such an array has been suggested earlier [ 3,4 ]. Several studies of the t-J model by Himeda, Kato and Ogata [ 4 ] and by Raczkowski et al [ 5 ], and Capello, Raczkowski and Poilblanc [ 6 ] have found that δ-phase shift domain walls cost very little energy or possibly even gain energy within RVB theory. These developments motivated us [ 7 ] to examine the energetics of the stripes looking for effects that can favor such a remarkable complex ordering .
1. Q. Li et al, Phys. Rev. Lett. 99, 067001 (2007) 2. E. Berg et al, Phys.Rev.Lett 99,127003 /2007) 3. S. C. Zhang, J. Phys. Chem. Solids 59, 1774 (1998) 4. A. Himeda, T. Kato and M. Ogata, Phys. Rev. Lett. 88,11701 (2002) 5. M. Raczkowski et al Phys. Rev. B76, 140505 82007) 6. M. Capello, M. Raczkowski and D. Poilblanc cond-mat 0801.2722 7. W.-Q. Chen ,K.-Y. Yang, T. M. Rice and F. C. Zhang in preparation. |
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