Semiconductivity in the double-zigzag-chain complex oxide RE<sub>2</sub>Ba<sub>2</sub>CuPtO<sub>8</sub> (RE identical to Y, Er, Ho)
N Toyota; P Koorevaar; J van der Berg; P H Kes; J A Mydosh; T Shishido; Y Saito; N Kuroda; K Ukei; T Sasaki; T Fukuda; N Toyota; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; P Koorevaar; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; J van der Berg; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; P H Kes; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; J A Mydosh; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; T Shishido; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; Y Saito; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; N Kuroda; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; K Ukei; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; T Sasaki; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands; T Fukuda; Kamerlingh Onnes Lab., Rijksuniv., Leiden, Netherlands
Журнал:
Journal of Physics: Condensed Matter
Дата:
1989-06-12
Аннотация:
The temperature dependence of electrical conductance has been measured on single crystals of the newly discovered oxide compound RE<sub>2</sub>Ba<sub>2</sub>CuPtO<sub>8</sub> (RE identical to Y, Er, Ho). This Pt- containing oxide is orthorhombic and has a characteristic double-zigzag chain of -O<sup>2</sup>-Pt<sup>4+</sup>-O<sup>2</sup>-Cu<sup>2+</sup>-O<sup>2</sup>- in columns running parallel to the b axis, which is the growth direction of the rectangular-shaped long-bar single crystals. All these compounds are found to be semiconductors with energy gaps of about 0.2-0.4 eV. They exhibit conductances proportional to exp(-T<sup>-1</sup>2/) rather than the thermally activated exp(-T<sup>-1</sup>) dependence. Such behaviour is discussed in terms of two models, namely one-dimensional variable-range hopping and the lattice-vibration-induced band-broadening effect.
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