Kim Young-June, Hill J P, Benthien H, Essler F H L, Jeckelmann E, Choi H S, Noh T W, Motoyama N, Kojima K M, Uchida S, Casa D, Gog T
Department of Physics, Brookhaven National Laboratory, Upton, New York 11973, USA.
Phys Rev Lett. 2004 Apr 2;92(13):137402. doi: 10.1103/PhysRevLett.92.137402.
We report a resonant inelastic x-ray scattering study of charge excitations in the quasi-one-dimensional Mott insulator SrCuO2. We observe a continuum of low-energy excitations, the onset of which exhibits a small dispersion of approximately 0.4 eV. Within this continuum, a highly dispersive feature with a large sinusoidal dispersion (approximately 1.1 eV) is observed. We have also measured the optical conductivity, and studied the dynamic response of the extended Hubbard model with realistic parameters, using a dynamical density-matrix renormalization group method. In contrast to earlier work, we do not find a long-lived exciton, but rather these results suggest that the excitation spectrum comprises a holon-antiholon continuum together with a broad resonance.
我们报道了对准一维莫特绝缘体SrCuO₂中电荷激发的共振非弹性X射线散射研究。我们观察到低能激发的连续谱，其起始表现出约0.4 eV的小色散。在这个连续谱内，观察到一个具有大约1.1 eV大正弦色散的高度色散特征。我们还测量了光导率，并使用动态密度矩阵重整化群方法，研究了具有实际参数的扩展哈伯德模型的动态响应。与早期工作不同，我们没有发现长寿命激子，而是这些结果表明激发谱由一个空穴-反空穴连续谱以及一个宽共振组成。
