Normal state tunneling conductance of perovskite oxides: Implications for high-Tc superconductors

Srikanth, H and Rajeev, KP and Shivashankar, GV and Raychaudhuri, AK (1992) Normal state tunneling conductance of perovskite oxides: Implications for high-Tc superconductors. In: Physica C: Superconductivity, 195 (1-2). pp. 87-92.

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Abstract

We have investigated tunneling conductances in disordered, normally conducting perovskite oxides close to the metal�insulator transition. We show that the normal state tunneling conductance of perovskite oxides can be cast in a general form G(V) = G0[1 + curly logical orV/V*curly logical orn] with 1?n?0.5 and where V* is an intrinsic energy scale. The exponent n graduall y increases from 0.5 to 1 as the metal-insulator (M-I) transition is approached. In the high-Tc Bi(2212) cuprates, the normally observed, linear G(V)(n=1) can be made sub-linear (n<1) by substitution of Ca with Y. From the similarity of the linear conductances, we suggest proximity to the M-I transition as a likely cause for this G(V)logical or, bar below V dependence. In systems showing linear conductances (nreverse similar, equals1), we find that ?G/?Vreverse similar, equalsG?0 with ?reverse similar, equals 1 and the intrinsic energy scale V*reverse similar, equals25�75 meV in the different oxides investigated.

Item Type:	Journal Article
Publication:	Physica C: Superconductivity
Publisher:	Elsevier science
Additional Information:	Copyright of this article belongs to Elsevier science.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	02 May 2011 05:46
Last Modified:	02 May 2011 05:46
URI:	http://eprints.iisc.ac.in/id/eprint/37283

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