标题： 局部非中心对称性和Sr$_3$Ru$_2$O$_7$中可能的自旋-动量锁定 显示英文标题

标题： Local noncentrosymmetricity and possible spin-momentum locking in Sr$_3$Ru$_2$O$_7$

摘要： 强自旋轨道耦合（SOC）之前被发现会在量子材料中产生显著效应，例如在拓扑绝缘体中发现的那些效应。 理论表明，由于Sr$_3$Ru$_2$O$_7$中RuO$_6$八面体的旋转导致的局部非中心对称性，也会产生有效的SOC\cite{SocSr327,MicroscopicnematicSr327}。 在沿特定平面内方向施加磁场的情况下，费米面被预测会发生重构。 此处我们报告了在单晶 Sr$_3$Ru$_2$O$_7$上进行的面内磁电阻和磁热电功率测量结果，其中电流传导或热电流沿特定晶体方向施加，磁场在$ab$平面内旋转（图1a），显示出在局部非中心对称性理论预测的磁场方向下具有最小值。 此外，当磁场垂直于热电流施加时，热电功率以及因此产生的电子熵被发现受到抑制，这表明在 Sr$_3$Ru$_2$O$_7$的费米面的大部分区域，自旋和动量被锁定，这很可能也是起源于局部非中心对称性。 显示英文摘要

摘要： Strong spin-orbital coupling (SOC) was found previously to lead to dramatic effects in quantum materials, such as those found in topological insulators. It was shown theoretically that local noncentrosymmetricity resulting from the rotation of RuO$_6$ octahedral in Sr$_3$Ru$_2$O$_7$ will also give rise to an effective SOC\cite{SocSr327,MicroscopicnematicSr327}. In the presence of a magnetic field applied along a specific in-plane direction, the Fermi surface was predicted to undergo a reconstruction. Here we report results of our in-plane magnetoresistivity and magnetothermopower measurements on single crystals of Sr$_3$Ru$_2$O$_7$ with an electrical or a thermal current applied along specific crystalline directions and a magnetic field rotating in the $ab$ plane (Fig. 1a), showing a minimal value for field directions predicted by the local noncentrosymmetricity theory. Furthermore, the thermopower, and therefore, the electron entropy, were found to be suppressed as the field was applied perpendicular to the thermal current, which suggests that the spin and the momentum in Sr$_3$Ru$_2$O$_7$ are locked over substantial parts of the Fermi surface, likely originating from local noncentrosymmetricity as well.