AI 中文总结
本研究以金红石型铌酸盐为对象，结合非弹性中子散射与机器学习声子计算，揭示室温下色散声子驱动Ni1+-Ni2+极化子跳跃的机制，证实该体系中存在自旋-电荷-声子耦合。
AI 中文摘要
理解晶格动力学如何介导极化子跳跃对设计多功能关联氧化物至关重要。本研究针对稀有室温磁介电体系金红石型铌酸盐，在其磁短程有序态下，证实了室温色散声子激发并阐明Ni1+-Ni2+极化子跳跃机制及罕见的自旋-电荷-声子耦合存在。研究采用非弹性中子散射（INS）揭示室温色散声子激发，辅以基于机器学习的声子计算，建立极化子跳跃机制的微观起源；实验上色散声子驱动极化子跳跃的证据稀缺，INS测量显示在21、33、47 meV处存在显著色散声子激发，表明集体晶格动力学可通过耦合电荷-自旋-声子相互作用实现离域极化子传播。色散声子与电荷载流子耦合，促进NiO6晶格发生关联畸变，助力离域极化子跳跃；4和8 meV处的低能磁激发表明NiO6八面体中存在局域短程磁关联或自旋-轨道耦合诱导的各向异性，相关内容已进行充分讨论。机器学习声子计算复现了实验观测到的声子激发，证实了与极化子产生导致的动态局域畸变兼容的晶格不稳定性。这些发现为金红石型氧化物体系中介导极化子跳跃的耦合电荷-自旋-声子机制提供了微观证据。
英文摘要
Understanding how lattice dynamics mediate polaron hopping is essential for designing multifunctional correlated oxides. Here, we demonstrate room-temperature dispersive phonon excitations and elucidate the Ni1+-Ni2+ polaron-hopping mechanism and the presence of rare spin-charge-phonon coupling even in a magnetically short-range-ordered state in rutile niobate, a rare room-temperature magnetodielectric system. We reveal room-temperature dispersive phonon excitations using inelastic neutron scattering (INS), complemented by machine-learning-based phonon calculations, to establish the microscopic origin of the polaron-hopping mechanism. Experimental evidence of dispersive phonon-driven polaron hopping is scarce. INS measurements show significant dispersive phonon excitations at 21, 33, and 47 meV, implying collective lattice dynamics that enable delocalized polaron propagation via coupled charge-spin-phonon interactions. Dispersive phonons couple to charge carriers and promote correlated NiO6 lattice distortions, facilitating delocalized polaron hopping. Low-energy magnetic excitations at 4 and 8 meV indicate the presence of local short-range magnetic correlations or spin-orbit-coupling-induced anisotropy in deformed NiO6 octahedra, which are thoroughly discussed. Machine-learning phonon calculations replicate the experimentally observed phonon excitations and demonstrate lattice instability, which is compatible with dynamic local distortions caused by polaron production. These findings provide microscopic evidence for a coupled charge-spin-phonon mechanism that mediates polaron hopping in rutile oxide systems.
Comments11 pages manuscript with 5 figures
