Charge dynamics in doped Mott insulators

✍ Scribed by Masanori Kohno; Xiao Hu; Masashi Tachiki

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 413 KB
• Volume: 412-414
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2003.11.077

✦ Synopsis

Charge dynamics in the two-dimensional Hubbard model is investigated by quantum Monte Carlo simulations. We find that dielectric function ðq; xÞ becomes negative at finite frequencies for U =t ¼ 4 with hole density d ¼ 0:15. Numerical results indicate that vertex corrections enhance charge fluctuations and that this enhancement is important for overscreening. Based on the numerical results, we briefly discuss phonon softening which is observed by X-ray and neutron inelastic scattering experiments.