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arXiv · 1310.3064

Enhanced low-energy magnetic excitations via suppression of the itinerancy in Fe0.98-zCuzTe0.5Se0.5

Jinsheng Wen·Shichao Li·Zhijun Xu·Cheng Zhang·M. Matsuda·O. Sobolev·J. T. Park·A. D. Christianson·E. Bourret-Courchesne·Qiang Li·Genda Gu·Dung-Hai Lee·J. M. Tranquada·Guangyong Xu·R. J. Birgeneau
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Abstract

We have performed resistivity and inelastic neutron scattering measurements on three samples of Fe0.98-zCuzTe0.5Se0.5 with z = 0, 0.02, and 0.1. It is found that with increasing Cu doping the sample's resistivity deviates progressively from that of a metal. However, in contrast to expectations that replacing Fe with Cu would suppress the magnetic correlations, the low-energy (no larger than 12 meV) magnetic scattering is enhanced in strength, with greater spectral weight and longer dynamical spin-spin correlation lengths. Such enhancements can be a consequence of either enlarged local moments or a slowing down of the spin fluctuations. In either case, the localization of the conduction states induced by the Cu doping should play a critical role. Our results are not applicable to models that treat 3d transition metal dopants simply as effective electron donors.

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Jinsheng Wen, Shichao Li, Zhijun Xu, Cheng Zhang, M. Matsuda, O. Sobolev, J. T. Park, A. D. Christianson, E. Bourret-Courchesne, Qiang Li, Genda Gu, Dung-Hai Lee, J. M. Tranquada, Guangyong Xu, R. J. Birgeneau. 2013-10-11. Enhanced low-energy magnetic excitations via suppression of the itinerancy in Fe0.98-zCuzTe0.5Se0.5. https://doi.org/10.1103/physrevb.88.144509

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