Interplay between charge-lattice interaction and strong electron correlations in cuprates: Phonon anomaly and spectral kinks

¹ SPIN-CNR and Dipartimento di Scienze Fisiche, Università di Napoli Federico II - I-80126 Napoli, Italy, EU
² SPIN-CNR and Dipartimento di Fisica “E. R. Caianiello”, Università di Salerno - I-84100 Salerno, Italy, EU
³ Cross-Correlated Materials Research Group (CMRG), ASI, RIKEN - Wako 351-0198, Japan
⁴ RRC “Kurchatov Institute” - 123182 Moscow, Russia
⁵ Department of Applied Physics, The University of Tokyo - 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan

^a giuliode@na.infn.it

Received: 31 May 2010
Accepted: 13 August 2010

Abstract

We investigate the interplay between strong electron correlations and charge-lattice interaction in cuprates. The coupling between half-breathing bond-stretching phonons and doped holes in the t-t′-J model is studied by the limited phonon basis exact diagonalization method. Nonadiabatic electron-phonon interaction leads to the splitting of the phonon spectral function at half-way to the zone boundary at and to low-energy kink feature in the electron dispersion, in agreement with experimental observations. Another kink due to strong electron correlation effects is observed at higher energy, depending on the strength of the charge-lattice coupling.