论文标题
二进制化合物的手性声子$ a $ bi（$ a $ = k，rb，cs）带有p2 $ _1 $/c结构
Chiral phonons in binary compounds $A$Bi ($A$ = K, Rb, Cs) with P2$_1$/c structure
论文作者
论文摘要
二进制化合物$ a $ a $ bi（$ a $ = k，rb，cs）在p2 $ _1 $ _1 $/c结构中结晶，其中含有顺时针和逆时针的手性链。电子带结构表现出这些系统的绝缘性质，带隙约为$ 0.25 $ ev。提出的动力学性能研究证实了该系统的稳定性，其中P2 $ _1 $/c对称性。晶体结构包含准二维BI链，表现出四倍的旋转``local''对称性。然而，该系统正式具有二倍的旋转对称性。与整个晶体的三倍（或更高）旋转对称轴无关，手性模式沿着这些系统中的双原子链传播。我们讨论了这些模式在单子手性链中的基本特性。我们表明，二倍旋转对称轴会影响手性声子的主要特性，手性声子在高对称点上并未实现，而是沿着它们之间的某些路径在相互空间中。另外，在掺杂系统中，手性声子具有非零的总角动量。
Binary compounds $A$Bi ($A$ = K, Rb, Cs) crystallize in P2$_1$/c structure containing both clockwise and anticlockwise chiral chains of Bi atoms. Electronic band structure exhibits the insulating nature of these systems, with the band gap about $0.25$ eV. The presented study of dynamical properties confirm a stability of the system with P2$_1$/c symmetry. The crystal structure contains the quasi-one-dimensional Bi chains, exhibiting four-fold-like rotational ``local'' symmetry. Nevertheless, the system formally posses two-fold rotational symmetry. Independently of the absence of the three-fold (or higher) rotational symmetry axes for the whole crystal, the chiral modes propagate along the Bi atom chains in these systems. We discuss basic properties of these modes in monoatomic chiral chains. We show that the two-fold rotational symmetry axis affects the main properties of the chiral phonons, which are not realized at the high-symmetry points, but along some paths between them in the reciprocal space. In addition, in the doped system, the chiral phonons possess non-zero total angular momentum.
