Topology in condensed matter physics manifests itself in the emergence of edge or surface states protected by underlying symmetries. We review two-dimensional topological insulators whose one-dimensional edge states are characterized by spin-momentum locking and protected by time-reversal symmetry. We focus in particular on their transport properties in the presence of electron interactions, which can allow the onset of different backscattering mechanisms, thus leading to deviations from the quantized conductance observed in the ballistic regime. The combined presence of helicity and electron interactions creates a new paradigm of the one-dimensional world called helical Luttinger liquid, whose theoretical properties and experimental observations are reviewed.

中文翻译：

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二维拓扑绝缘体中的边缘物理

凝聚态物理中的拓扑结构表现为边缘或表面状态受基础对称性保护的状态。我们回顾了二维拓扑绝缘体，其一维边缘状态以自旋动量锁定为特征，并受到时间反转对称性的保护。在电子相互作用的存在下，我们特别关注它们的传输性质，这可能导致出现不同的背向散射机制，从而导致与弹道状态下观察到的量化电导有所偏差。螺旋和电子相互作用的共同存在创造了一维世界的新范式，称为螺旋Luttinger液体，其理论性质和实验观察得到了综述。