We performed polarized reflection and transmission measurements on the layered conducting oxide PdCoO₂ thin films. For the ab-plane, an optical peak near Ω ≈ 750 cm⁻¹ drives the scattering rate 1/τ(ω) and effective mass m^*(ω) of the Drude carrier to increase and decrease respectively for ω ≧ Ω. For the c-axis, a longitudinal optical phonon (LO) is present at Ω as evidenced by a peak in the loss function Im[−1/ε_c(ω)]. Further polarized measurements in different light propagation (q) and electric field (E) configurations indicate that the Peak at Ω results from an electron-phonon coupling of the ab-plane carrier with the c-LO phonon, which leads to the frequency-dependent 1/τ(ω) and m^*(ω). This unusual interaction was previously reported in high-temperature superconductors (HTSC) between a non-Drude, mid-infrared (IR) band and a c-LO. On the contrary, it is the Drude carrier that couples in PdCoO₂. The coupling between the ab-plane Drude carrier and c-LO suggests that the c-LO phonon may play a significant role in the characteristic ab-plane electronic properties of PdCoO₂, including the ultra-high dc-conductivity, phonon-drag, and hydrodynamic electron transport.

我们对层状导电氧化物 PdCoO₂ 薄膜进行了偏振反射和透射测量。对于ab平面，光学峰值接近Ω ≈ 750 cm⁻¹ 驱动散射率 1/τ(ω，包括超-高直流电导率、声子阻力和流体动力电子传输。₂PdCoO的平面电子特性ba-LO 声子可能在特性中发挥重要作用c-LO 表明c面德鲁德载体与ba 中耦合的是 Drude 载流子。 ₂-LO 之间的相互作用。相反，在 PdCoOc)。这种不寻常的相互作用之前曾在高温超导体 (HTSC) 中报道过非德鲁德中红外 (IR) 波段和 ω 轴，Ω 处存在纵向光学声子 (LO)，损失函数 Im[−1/< 中的峰值证明了这一点/span>^*m) 和 ω(τ-LO 声子，这导致频率相关的 1/c 平面载流子的电子-声子耦合产生的与 ba) 配置表明 Ω 处的峰值是由 E) 和电场 (q)] 。在不同光传播 (ω(_cεc Ω。对于 ≧ω) 分别增加和减少 德鲁德载波的 ω(^*m) 和有效质量