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Variable-range hopping conductivity in the copper-oxygen chains of La_3Sr_3Ca_8Cu_24O_41

T. Vuletic·B. Korin-Hamzic·S. Tomic·B. Gorshunov·P. Haas·M. Dressel·J. Akimitsu·T. Sasaki·T. Nagata
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Abstract

We show that the spin chain/ladder compound La_3Sr_3Ca_8Cu_24O_41 is an insulator with hopping transport along the chains. In the temperature range 35 - 280 K, DC conductivity sigma_{DC}(T) follows Mott's law of variable-range hopping conduction; the frequency dependence has the form sigma(ν, T) = σ_{DC}(T) + A(T)ν^{s}, where s \approx 1. The conduction mechanism changes from variable-range hopping to nearest-neighbor hopping around T_{c} =300 K. The chain array thus behaves like a one-dimensional disordered system. Disorder is due to random structural distortions of chains induced by irregular coordination of the La/Sr/Ca ions.

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T. Vuletic, B. Korin-Hamzic, S. Tomic, B. Gorshunov, P. Haas, M. Dressel, J. Akimitsu, T. Sasaki, T. Nagata. 2003-04-10. Variable-range hopping conductivity in the copper-oxygen chains of La_3Sr_3Ca_8Cu_24O_41. https://doi.org/10.1103/physrevb.67.184521

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