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-3d and O-2p orbital character owing to the strong hybridization of these orbitals near the Fermi level. Here, we investigate underdoped Bi₂Sr_1.4La_0.6CuO_6+δ 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 (CuO₂) 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 Bi₂Sr_1.8La_0.2CuO_6+δ, where neither CDWs nor phonon anomalies appear, we highlight that a sharp intensity anomaly is induced in the proximity of the CDW wavevector (Q_CDW) for the bond-buckling phonon, in concert with the diffused intensity enhancement of the bond-stretching phonon at wavevectors much greater than Q_CDW. 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.

电荷密度波（CDW）在掺杂不足的铜酸盐超导体中无处不在。作为价电子密度的调节，由于这些轨道在费米能级附近的强杂交，空穴掺杂的铜酸盐中的CDW具有Cu-3 d和O-2 p轨道特征。在这里，我们使用共振非弹性X射线散射（RIXS）研究了掺杂不足的Bi ₂ Sr _1.4 La _0.6 CuO _{6 +δ，}并发现在氧化铜（CuO ₂）具有可比的周期性和相关长度的平面。此外，我们发现了伴随CDW的键伸展和键屈曲声子异常。与稍微超掺杂的Bi ₂ Sr _1.8 La _0.2 CuO _{6 +δ相比}，CDW和声子均未出现异常，我们着重指出，在键屈曲声子的CDW波矢（Q _CDW）附近会引起强烈的强度异常，与波矢量远大于Q _CDW的键拉伸声子的扩散强度增强相一致。我们的结果提供了准静态CDW，其色散激发以及相关的电子-声子异常的全面情况，这对于理解铜酸盐中竞争的电子不稳定性至关重要。