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We have investigated the metallic ground state of the extremely anisotropic quasi-one-dimensional metal PrBa2Cu4O8 (tb2: ta2: tc2 ~ 4000: 2: 1), the non-superconducting analogue of the high-Tc cuprate YBa2Cu4O8, as a function of disorder content, introduced either through atomic-site substitution or electron irradiation [1, 2]. A common single disorder threshold is found to drive interchain and intrachain resistivities into a low temperature regime where they display dρ/dT < 0. The survival of a large magnetoresistance of orbital origin reveals the itinerancy of the electronic system not to be suppressed by the presence of disorder [3]. We propose an interpretative scenario based on a microscopic electronic fragmentation of the metallic chains, though in contrast to many previous theoretical proposals, coherent hopping between chains appears to remain a relevant perturbation within the disordered system.
[1] New J. Phys. 8 (2006) 172-183; [2] Phys. Rev. Lett. vol. 99, 136402 (2007); [3] Phys. Rev. Lett. vol. 98, 146601 (2007). |
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