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arXiv · 1610.05337

Observation of semi-localized dispersive states in the strongly correlated electron-doped ferromagnet Eu$_{1-x}$Gd$_{x}$O

Daniel E. Shai·Mark H. Fischer·Alex J. Melville·Eric J. Monkman·John W. Harter·Dawei Shen·Darrell G. Schlom·Michael J. Lawler·Eun-Ah Kim·Kyle M. Shen
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Abstract

Chemical substitution plays a key role in controlling the electronic and magnetic properties of complex materials. For instance, in EuO, carrier doping can induce a spin-polarized metallic state, colossal magnetoresistance, and significantly enhance the Curie temperature. Here, we employ a combination of molecular-beam epitaxy, angle-resolved photoemission spectroscopy, and an effective model calculation to investigate and understand how semi-localized states evolve in lightly electron doped Eu$_{1-x}$Gd$_{x}$O above the ferromagnetic Curie temperature. Our studies reveal a characteristic length scale for the spatial extent of the donor wavefunctions which remains constant as a function of doping, consistent with recent tunneling studies of doped EuO. Our work sheds light on the nature of the semiconductor-to-metal transition in Eu$_{1-x}$Gd$_{x}$O and should be generally applicable for doped complex oxides.

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Daniel E. Shai, Mark H. Fischer, Alex J. Melville, Eric J. Monkman, John W. Harter, Dawei Shen, Darrell G. Schlom, Michael J. Lawler, Eun-Ah Kim, Kyle M. Shen. 2016-10-17. Observation of semi-localized dispersive states in the strongly correlated electron-doped ferromagnet Eu$_{1-x}$Gd$_{x}$O. https://doi.org/10.1103/physrevb.94.195102

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