paper

Doping-dependent phonon anomaly and charge-order phenomena in the HgBa $_{2}$ CuO $_{4 + I^´}$ and HgBa $_{2}$ CaCu $_{2}$ O $_{6 + I^´}$

arXiv:1910.08254 · doi:10.1103/PhysRevB.101.220509

Abstract

Using resonant X-ray diffraction and Raman spectroscopy, we study charge correlations and lattice dynamics in two model cuprates, HgBa $_{2}$ CuO $_{4 + I^´}$ and HgBa $_{2}$ CaCu $_{2}$ O $_{6 + I^´}$ . We observe a maximum of the characteristic charge order temperature around the same hole concentration ( $p \approx 0.09$ ) in both compounds, and concomitant pronounced anomalies in the lattice dynamics that involve the motion of atoms in and/or adjacent to the CuO $_{2}$ layers. These anomalies are already present at room temperature, and therefore precede the formation of the static charge correlations, and we attribute them to an instability of the CuO $_{2}$ layers. Our finding implies that the charge order in the cuprates is an emergent phenomenon, driven by a fundamental variation in both lattice and electronic properties as a function of doping.

4 pages, 3 figures, supplemental material available upon request

Doping-dependent phonon anomaly and charge-order phenomena in the HgBa2​CuO4+I^´​ and HgBa2​CaCu2​O6+I^´​

Abstract

Doping-dependent phonon anomaly and charge-order phenomena in the HgBa $_{2}$ CuO $_{4 + I^´}$ and HgBa $_{2}$ CaCu $_{2}$ O $_{6 + I^´}$