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arXiv · 1502.04003

Observation of low energy dispersive modes in un- derdoped (La, Nd) 2--x Sr x CuO 4

Matteo D 'Astuto·Sylvain Denis·Jeff Graf·Alessandra Lanzara·Claudia Decorse·Paola Giura·Sang-Wook Cheong·Abhay Shukla·Patrick Berthet·Daniel Lamago·John-Paul Castellan·Alexei Bossak·Michael Krisch
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Abstract

We find excitations lower in energy than known phonon modes in underdoped La$\_{2-x}$Sr$\_x$CuO$\_{4+\delta}$ (x=0.08), with both inelastic X-Ray scattering (IXS) and inelastic neutron scattering (INS). A non dispersive excitation at 9 meV is identified and is also seen by INS in (La,Nd)$\_{2-x}$Sr$\_x$CuO$\_{4+\delta}$, with 40$\%$ Nd substitution. INS also identifies a still lower energy dispersive mode at low q in the Nd free sample. These modes are clearly distinct from the longitudinal acoustic phonon and correspond in energy to the Zone Centre modes measured by optical spectroscopy and associated with stripe dynamics.

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Matteo D 'Astuto, Sylvain Denis, Jeff Graf, Alessandra Lanzara, Claudia Decorse, Paola Giura, Sang-Wook Cheong, Abhay Shukla, Patrick Berthet, Daniel Lamago, John-Paul Castellan, Alexei Bossak, Michael Krisch. 2015-02-13. Observation of low energy dispersive modes in un- derdoped (La, Nd) 2--x Sr x CuO 4. https://arxiv.org/abs/1502.04003

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