O K-edge RIXS energy dependence of low-energy excitations in underdoped La(2-x)SrxCuO4
The insulator to superconductor phase boundary is a poorly understood region of the phase diagram of the cuprates. A better understanding of the electronic structure of these complex materials in this crucial region would probably represent a major step towards a theory of high temperature superconductivity. In particular, it has been proposed that persistent magnetic fluctuations could provide the pairing “glue” . In this study, we have used Resonant Inelastic x-ray Scattering (RIXS), a novel probe of electronic and magnetic excitations in solids. We have investigated the low-energy excitations at O K-edge in the paradigmatic cuprate material La(2-x)SrxCuO4 (LSCO), as a function of doping ranging from an insulator to a bad metal (superconductor). We identify the signatures of bimagnon excitations, which persist in the underdoped superconductor. Remarkably, we have been able to resolve a double peak structure at 2 eV, for which previous theoretical calculations suggest a Zhang-Rice singlet nature [2-3].
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Record created on 2015-03-19, modified on 2016-08-09