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arXiv · 1508.07841

Formation and observation of a quasi-two-dimensional $d_{xy}$ electron liquid in epitaxially stabilized Sr$_{2-x}$La$_{x}$TiO$_{4}$ thin films

Y. F. Nie·D. Di Sante·S. Chatterjee·P. D. C. King·M. Uchida·S. Ciuchi·D. G. Schlom·K. M. Shen
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Abstract

We report the formation and observation of an electron liquid in Sr$_{2-x}$La$_{x}$TiO$_4$, the quasi-two-dimensional counterpart of SrTiO$_3$, through reactive molecular-beam epitaxy and {\it in situ} angle-resolved photoemission spectroscopy. The lowest lying states are found to be comprised of Ti 3$d_{xy}$ orbitals, analogous to the LaAlO$_3$/SrTiO$_3$ interface and exhibit unusually broad features characterized by quantized energy levels and a reduced Luttinger volume. Using model calculations, we explain these characteristics through an interplay of disorder and electron-phonon coupling acting co-operatively at similar energy scales, which provides a possible mechanism for explaining the low free carrier concentrations observed at various oxide heterostructures such as the LaAlO$_3$/SrTiO$_3$ interface.

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Y. F. Nie, D. Di Sante, S. Chatterjee, P. D. C. King, M. Uchida, S. Ciuchi, D. G. Schlom, K. M. Shen. 2015-08-31. Formation and observation of a quasi-two-dimensional $d_{xy}$ electron liquid in epitaxially stabilized Sr$_{2-x}$La$_{x}$TiO$_{4}$ thin films. https://doi.org/10.1103/physrevlett.115.096405

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