On the contribution of nearly critical spin and charge collective modes to the Raman spectra of high-Tc cuprates

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:321

Article; Proceedings Paper

Caprara, S.¹  Di Castro, C.¹  Enss, T.²  Grilli, M.¹ 

[1] Univ Roma La Sapienza, Dipartimento Fis, I-00185 Rome, Italy

[2] Tech Univ Munich, Dept Phys, D-85747 Garching, Germany

关键词: Raman and optical spectrum;    Quantum criticality;    Stripe;   

DOI  :  10.1016/j.jmmm.2008.11.025

来源: Elsevier

【 摘 要 】

We discuss how Raman spectra are affected by nearly critical spin and charge collective modes, which are coupled to charge carriers near a stripe quantum critical point. We show that specific fingerprints of nearly critical collective modes can indeed be observed in Raman spectra and that the selectivity of Raman spectroscopy in momentum space may also be exploited to distinguish the spin and charge contribution. We apply our results to discuss the spectra of high-T-c superconducting cuprates finding that the collective modes should have masses with substantial temperature dependence in agreement with their nearly critical character. Moreover, spin modes should be more diffusive than charge modes indicating that in stripes the charge is nearly ordered, while spin modes are strongly overdamped and fluctuate with high frequency. (C) 2008 Elsevier B. V. All rights reserved.

【 授权许可】

Free