Lorenz number in low-dimensional structures

Folded sheets appear to behave as a quasi one or two-dimensional system depending on temperature and radius of the tubes. The Lorenz number for such a system is obtained and it is concluded that for unfolded sheets, which show 2-D behavior, the Lorenz number may fall sharply at very low temperature. On relatively high temperature side, the Lorenz number acquires a constant value, close to the usual metallic behavior, whereas in 1-D systems the Lorenz value is smaller than usual, but is not expected to fall with the lowering of temperature. (C) 2010 Elsevier B.V. All rights reserved.