Coexistence of Midgap Antiferromagnetic and Mott States in Undoped, Hole- and Electron-Doped Ambipolar Cuprates

Abstract

We report the first observation of the coexistence of a distinct midgap state and a Mott state in undoped and their evolution in electron and hole-doped ambipolar Y(0.38)La(0.62)dBa(0.82)La(0.18))(2)Cu3Oy films using spectroscopic ellipsometry and x-ray absorption spectroscopies at the O K and Cu L-3,L-2 edges. Supported by theoretical calculations, the midgap state is shown to originate from antiferromagnetic correlation. Surprisingly, while the magnetic state collapses and its correlation strength weakens with dopings, the Mott state in contrast moves toward a higher energy and its correlation strength increases. Our result provides important clues to the mechanism of electronic correlation strengths and superconductivity in cuprates.

Publication
PHYSICAL REVIEW LETTERS 116, (2016).
Date
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