论文标题
掺杂的SR14-XCAXCU24O41 Cuprate梯子的高能自旋波动从集体三倍到局部磁激发的跨界
Crossover of the high-energy spin fluctuations from collective triplons to localized magnetic excitations in doped Sr14-xCaxCu24O41 cuprate ladders
论文作者
论文摘要
我们使用CU L_3-边缘谐振X射线散射（RIXS）研究了SR_（14-X）CA_X CU_24 O_41（SCCO）SR_（14-X）CA_X CU_24 O_41（SCCO）中的磁激励（Q-1D）梯子。通过将动量分辨的RIX光谱与（x = 12.2）和没有（x = 0）高CA含量进行比较，我们跟踪磁激发从集体两型两层激发（2T）激发（x = 0）到弱分散的差距模式的演变，该模式在280 mev（x = 12.2）的能量时（x = 12.2）。掺杂梯子中RIX响应的密度矩阵重新归一化组（DMRG）计算表明，在X = 12.2处观察到的扁平磁性分散体和阻尼激发曲线源自增强的孔定位。这种解释得到了依赖于极化的RIX测量值的支持，在rixs频谱中，我们将旋转的ΔS= 0散射从主要的ΔS= 1个旋转绑带信号。结果表明，当SR被CA取代时，ΔS= 0通道中的低能量会耗尽，这与载流子迁移率的降低一致。我们的结果表明，离线杂质可以影响Cuo_4 plaquettes中的低能磁激发和超导相关性。最后，我们的研究表征了在高压压力下SCCO中超导性出现的相位的磁性和电荷波动。
We studied the magnetic excitations in the quasi-one-dimensional (q-1D) ladder subsystem of Sr_(14-x) Ca_x Cu_24 O_41(SCCO) using Cu L_3-edge resonant inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra with (x=12.2) and without (x=0) high Ca content, we track the evolution of the magnetic excitations from collective two-triplon (2T) excitations (x=0) to weakly-dispersive gapped modes at an energy of 280 meV (x=12.2). Density matrix renormalization group (DMRG) calculations of the RIXS response in the doped ladders suggest that the flat magnetic dispersion and damped excitation profile observed at x=12.2 originates from enhanced hole localization. This interpretation is supported by polarization-dependent RIXS measurements, where we disentangle the spin-conserving ΔS=0 scattering from the predominant ΔS=1 spin-flip signal in the RIXS spectra. The results show that the low-energy weight in the ΔS=0 channel is depleted when Sr is replaced by Ca, consistent with a reduced carrier mobility. Our results demonstrate that off-ladder impurities can affect both the low-energy magnetic excitations and superconducting correlations in the CuO_4 plaquettes. Finally, our study characterizes the magnetic and charge fluctuations in the phase from which superconductivity emerges in SCCO at elevated pressures.
