AI 中文总结
研究通过对高质量单晶CeRh₂As₂进行NQR和NMR测量，揭示其超导多相源于交错Rashba自旋轨道耦合。发现高质量样品中AFM转变更明显，Tₙ与Tₛₙ接近，NQR光谱暗示磁结构二维非相称调制，还表明T₀处有缓慢波动AFM序，Tₙ处变为静态。
AI 中文摘要
我们对高质量单晶CeRh₂As₂进行了⁷⁵As核四极共振（NQR）和核磁共振（NMR）测量，它是一种重费米子超导体，在沿c轴的磁场下呈现多个超导（SC）相。该SC多相被认为源于与局部反演对称性破坏相关的交错Rashba自旋轨道耦合。除超导外，早期样品中CeRh₂As₂在T₀~0.5 K以下呈现I相，在Tₙ~0.25 K以下呈现反铁磁（AFM）态。在高质量样品中，AFM转变更明显，Tₙ增加到几乎与Tₛₙ重合。As(1)位点的NQR光谱暗示内部场具有非相称分布，表明在Q = 0的A型AFM分量上叠加了磁结构的二维非相称调制。此外，在远高于Tₙ的T₀处NQR强度明显下降，在Tₙ处内部场突然增加，表明在T₀处出现了缓慢波动的AFM序，在Tₙ处变为静态。
英文摘要
We performed $^{75}$As nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) measurements on a higher-quality single-crystalline CeRh$_2$As$_2$, a heavy-fermion superconductor exhibiting multiple superconducting (SC) phases under magnetic fields along the $c$ axis. This SC multiphase is believed to originate from staggered Rashba spin-orbit coupling associated with locally broken inversion symmetry. In addition to superconductivity, CeRh$_2$As$_2$ exhibits phase I below $T_0\sim0.5$ K and an antiferromagnetic (AFM) state below $T_{N}\sim 0.25$ K in the early-stage samples. In the higher-quality sample, the AFM transition becomes more pronounced, and $T_{N}$ increases to nearly coincide with $T_{SC}$. The NQR spectra at the As(1) site imply an internal field with an incommensurate distribution, indicating a two-dimensional incommensurate modulation of the magnetic structure superimposed on a $Q=0$ A-type AFM component. Moreover, a pronounced decrease in the NQR intensity at $T_0$ well-above $T_{N}$ and an abrupt increase in the internal field at $T_{N}$ suggest the emergence of a slowly fluctuating AFM order at $T_0$ which becomes static at $T_{N}$.
