Charge-Density-Excitation Spectrum in the t?t′?J?V Model

ANDRÉS GRECO; YAMASE, HIROYUKI; MATÍAS BEJAS

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN

PHYSICAL SOC JAPAN

Año: 2017 vol. 86 p. 1 - 5

0031-9015

We study the density?density correlation function in a large-N scheme of the t?t'?J?V model. When the nearest-neighbor Coulomb interaction V is zero, our model exhibits phase separation in a wide doping region and we obtain large spectral weight near momentum q = (0;0) at low energy, which originates from the proximity to phase  separation.These features are much stronger for electron doping than for hole doping. However, once phase separation is suppressed by including a finite V, the low-energy spectral weight around q = (0;0) is  substantially suppressed. Instead a sharp zero-sound mode is stabilized above the particle?hole continuum. We discuss that the presence of a moderate value of V, which is frequently neglected in the t?J model, is important to understand low-energy charge excitations especially close to q = (0;0) for electron doping. This insight should be taken into account in a future study of x-rayscattering measurements.