Resonant inelastic x-ray scattering at the N $K$ edge reveals clearly resolved harmonics of the anion plane vibrations in the $\kappa$-(BEDT-${\mathrm{TTF})}_2{\mathrm{Cu}}_2$(${\mathrm{CN})}_3$ spin-liquid insulator. Tuning the incoming light energy at the $K$ edge of two distinct N sites permits us to excite different sets of phonon modes. The cyanide (CN) stretching mode is selected at the edge of the ordered N sites which are more strongly connected to the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) molecules, while positionally disordered N sites show multimode excitation. Combining measurements with calculations on an anion plane cluster permits us to estimate the site-dependent electron-phonon coupling of the modes related to nitrogen excitation.

中文翻译：

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共振非弹性X射线散射探测自旋液体κ-（BEDT-TTF）2Cu2（CN）3中的电子-声子耦合

N处的共振非弹性X射线散射 $ķ$ 边缘揭示了阴离子平面中振动的清晰分解的谐波 $\kappa$-（BEDT-${\mathrm{特遣队}）}_{\mathrm{2个}}{铜}_{\mathrm{2个}}$（${\mathrm{CN}）}_3$自旋液体绝缘体。调整入射光的能量$ķ$两个不同的N位点的边缘允许我们激发不同的声子模式集。在有序的N位点的边缘选择氰化物（CN）拉伸模式，该N位点的位置与双（亚乙基二硫代）四硫富瓦烯（BEDT-TTF）分子更牢固地连接，而位置无序的N位点显示出多模激发。将测量结果与阴离子平面簇上的计算结果相结合，使我们能够估计与氮激发有关的模式的与位置有关的电子-声子耦合。