The metal-insulator transition (MIT) has been studied in Ba0:9Nd0:1CuO2x=CaCuO2 ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance R, eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of R close to the 25:8 kuniversal quantum resistance. All data confirm the assumption that each CaCuO2 layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel.
Direct measurement of sheet resistance R in cuprate systems: evidence of fermionic scenario in Metal-Insulator Transition
TAFURI, Francesco;
2007
Abstract
The metal-insulator transition (MIT) has been studied in Ba0:9Nd0:1CuO2x=CaCuO2 ultrathin cuprate structures. Such structures allow for the direct measurement of the 2D sheet resistance R, eliminating ambiguity in the definition of the effective thickness of the conducting layer in high temperature superconductors. The MIT occurs at room temperature for experimental values of R close to the 25:8 kuniversal quantum resistance. All data confirm the assumption that each CaCuO2 layer forms a 2D superconducting sheet within the superconducting block, which can be described as weak-coupled equivalent sheets in parallel.File in questo prodotto:
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