Multiorbital charge-density wave excitations and concomitant phonon anomalies in Bi<sub>2</sub>Sr<sub>2</sub>LaCuO<sub>6+δ</sub>.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 32586955.
- Also identified by DOI 10.1073/pnas.2001755117 and PMC identifier 7368327.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Charge-density waves (CDWs) are ubiquitous in underdoped cuprate superconductors. As a modulation of the valence electron density, CDWs in hole-doped cuprates possess both Cu-3<i>d</i> and O-2<i>p</i> orbital character owing to the strong hybridization of these orbitals near the Fermi level. Here, we investigate underdoped Bi<sub>2</sub>Sr<sub>1.4</sub>La<sub>0.6</sub>CuO<sub>6+δ</sub> using resonant inelastic X-ray scattering (RIXS) and find that a short-range CDW exists at both Cu and O sublattices in the copper-oxide (CuO<sub>2</sub>) planes with a comparable periodicity and correlation length. Furthermore, we uncover bond-stretching and bond-buckling phonon anomalies concomitant to the CDWs. Comparing to slightly overdoped Bi<sub>2</sub>Sr<sub>1.8</sub>La<sub>0.2</sub>CuO<sub>6+δ</sub>, where neither CDWs nor phonon anomalies appear, we highlight that a sharp intensity anomaly is induced in the proximity of the CDW wavevector (Q<sub>CDW</sub>) for the bond-buckling phonon, in concert with the diffused intensity enhancement of the bond-stretching phonon at wavevectors much greater than Q<sub>CDW</sub> Our results provide a comprehensive picture of the quasistatic CDWs, their dispersive excitations, and associated electron-phonon anomalies, which are key for understanding the competing electronic instabilities in cuprates.