1. Metal-semiconductor-transition observed in Bi2Ca(Sr, Ba)2Co2O8+δ single crystals.
- Author
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Song-Tao Dong, Bin-Bin Zhang, Lun-Yong Zhang, Chen, Y. B., Shu-Hua Yao, Jian Zhou, Shan-Tao Zhang, Zheng-Bin Gu, and Yan-Feng Chen
- Subjects
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METAL-semiconductor-metal structures , *ANDERSON localization , *FERMI level , *MAGNETORESISTANCE , *BISMUTH alloys , *SEEBECK coefficient , *SINGLE crystals - Abstract
Electrical property evolution of Bi2AE2Co2O8+δ single crystals (AE = Ca, Sr and Ba) is systematically explored. When AE changes from Ca to Ba, the electrical property of Bi2Ca2Co2O8+δ and Bi2Sr2Co2O8+δ demonstrates semiconductor-like properties. But Bi2Ba2Co2O8+δ shows the metallic behavior. Analysis of temperature-dependent resistance substantiates that from metallic Bi2Ba2Co2O8+δ to semiconductor-like Bi2Sr2Co2O8+δ can be attributed to Anderson localization. However the semiconductor behaviour of Bi2Sr2Co2O8+δ and Bi2Ca2Co2O8+δ is related to electronic correlations effect that is inferred by large negative magnetoresistance (70%). The theoretical electronic structures and valence X-ray photoemission spectroscopy substantiate that there is a relative large density of state around Fermi level in Bi2Ba2Co2O8+δ compared with other two compounds. It suggests that Bi2Ba2Co2O8+δ is more apt to be metal in this material system. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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