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Electron-Hole Asymmetry in GdBaCo_{2}O_{5+x}: Evidence for Spin Blockade of Electron Transport in a Correlated Electron System

A. A. Taskin·Yoichi Ando
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Abstract

In RBaCo_{2}O_{5+x} compounds (R is rare earth) variability of the oxygen content allows precise doping of CoO_2 planes with both types of charge carriers. We study transport properties of doped GdBaCo_{2}O_{5+x} single crystals and find a remarkable asymmetry in the behavior of holes and electrons doped into a parent insulator GdBaCo_{2}O_{5.5}. Doping dependences of resistivity, Hall response, and thermoelectric power reveal that the doped holes greatly improve the conductivity, while the electron-doped samples always remain poorly conducting. This doping asymmetry provides strong evidence for a spin blockade of the electron transport in RBaCo_{2}O_{5+x}.

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A. A. Taskin, Yoichi Ando. 2005-09-27. Electron-Hole Asymmetry in GdBaCo_{2}O_{5+x}: Evidence for Spin Blockade of Electron Transport in a Correlated Electron System. https://doi.org/10.1103/physrevlett.95.176603

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