AI 中文总结
研究针对手性单分子中CISS效应实验结果矛盾的问题，开发含几何自旋轨道耦合和环境退相干的理论框架，计算发现CISS效应在不同区域的变化及相关影响因素，统一了矛盾观察结果，为统一CISS现象提供基础。
AI 中文摘要
一些研究报告了四类具有显著自旋极化的手性单分子中清晰的手性诱导自旋选择性（CISS）效应。然而，最近近千次单独测试的高精度测量未能在相同分子系统中检测到显著的CISS信号。为解决这一差异，我们开发了一个包含几何自旋轨道耦合和环境退相干的理论框架，用于系统研究四种不同几何形状和尺寸的手性单分子中的CISS。计算表明，CISS效应在强相干和强退相干区域完全被抑制，但在中间退相干区域变得明显，出现可观测的自旋极化。在强相干区域，电子 - 电子相互作用和电子 - 振动耦合增强CISS效应，前者在大分子中更有效，后者在小分子中作用更显著。升高温度进一步增强自旋极化。该机制统一了相互矛盾的实验观察结果，并揭示了CISS效应如何从规则螺旋（螺旋对称）演变为不规则螺旋（点对称或轴对称）手性。此框架为统一单分子系统中的CISS现象提供了基础，无论其具体分子构型或对称类别如何。
英文摘要
Some studies have reported clear chirality-induced spin selectivity (CISS) effect in four classes of chiral single molecules with remarkable spin polarization. In contrast, a recent high-precision measurement involving nearly a thousand individual tests failed to detect significant CISS signals in the same molecular systems (J. Am. Chem. Soc. 2025, \textbf{147}, 25043). These conflicting results cast doubt on whether CISS truly occurs in these chiral systems at the single-molecular level. To resolve this discrepancy, we develop a theoretical framework incorporating geometric spin-orbit coupling and environmental decoherence, enabling systematic study of the CISS in four chiral single molecules with distinct geometries and sizes. Our calculations show that the CISS effect is completely suppressed in both strong-coherence and strong-decoherence regimes, but becomes pronounced in the intermediate-decoherence regime, where observable spin polarization emerges. In the strong-coherence regime, both electron-electron interaction and electron-vibration coupling enhance the CISS effect: the former is more effective in large molecules, whereas the latter plays a more significant role in smaller ones. Increasing temperature further enhances spin polarization. The proposed mechanism unifies contradictory experimental observations and reveals how the CISS effect evolves from regular helical (helical symmetric) to irregular helical (point-symmetric or axially symmetric) chirality. This framework thus provides a basis for unifying CISS phenomena across single-molecule systems, regardless of their specific molecular configurations or symmetry classes.
Comments10 Pages, 5 figures
