Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide
Spontaneous gyrotropic electronic order in a transition-metal dichalcogenide
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DOI：
10.1038/s41586-020-2011-8
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发表时间：
2019-10
期刊：
影响因子：
64.8
通讯作者：
Su-Yang Xu;Q. Ma;Yang Gao;A. Kogar;A. Zong;Andrés M. Mier Valdivia;T. Dinh;Shin-Ming Huang;
中科院分区：
文献类型：
--
作者：
Su-Yang Xu;Q. Ma;Yang Gao;A. Kogar;A. Zong;Andrés M. Mier Valdivia;T. Dinh;Shin-Ming Huang;
手性在自然界中普遍存在，相反手性的种群在基本水平上是惊人的不对称。例子从亚原子弱力的宇称破坏到生物分子的同手性。实现手性选择性合成（手性诱导）的能力在立体化学、分子生物学和药理学中具有重要意义。在凝聚态物理学中，当晶体电子系统缺乏镜像平面、空间反转中心或旋转反转轴时，它是几何手性的。通常，几何手性由材料的手性晶格结构预定义，其在晶体形成时固定。相比之下，在旋光有序材料中，，-，电子自发地组织自己，在最初的非手性晶格中表现出宏观手性。尽管这种有序--被认为是液晶的量子模拟--已经引起了人们的极大兴趣，但迄今为止还没有对旋光有序进行明确的观察或操纵。在这里，我们报告了光学手征感应的实现以及过渡金属二硫属化合物半金属1 T-TiSe 2中旋光有序相的观察。我们发现，照射中红外圆偏振光的1 T-TiSe 2，而冷却到临界温度以下，导致优先形成一个手性域。该状态的手征性通过测量平面外圆形光电流来证实，其方向取决于光感应。虽然畴壁的作用需要进一步的调查与本地探针，这里展示的方法可以应用于实现和控制其他量子材料中的手性电子相。
Chirality is ubiquitous in nature, and populations of opposite chiralities are surprisingly asymmetric at fundamental levels,. Examples range from parity violation in the subatomic weak force to homochirality in biomolecules. The ability to achieve chirality-selective synthesis (chiral induction) is of great importance in stereochemistry, molecular biology and pharmacology. In condensed matter physics, a crystalline electronic system is geometrically chiral when it lacks mirror planes, space-inversion centres or rotoinversion axes. Typically, geometrical chirality is predefined by the chiral lattice structure of a material, which is fixed on formation of the crystal. By contrast, in materials with gyrotropic order, , –, electrons spontaneously organize themselves to exhibit macroscopic chirality in an originally achiral lattice. Although such order—which has been proposed as the quantum analogue of cholesteric liquid crystals—has attracted considerable interest, , , , , , , , , , , –, no clear observation or manipulation of gyrotropic order has been achieved so far. Here we report the realization of optical chiral induction and the observation of a gyrotropically ordered phase in the transition-metal dichalcogenide semimetal 1T-TiSe2. We show that shining mid-infrared circularly polarized light on 1T-TiSe2while cooling it below the critical temperature leads to the preferential formation of one chiral domain. The chirality of this state is confirmed by the measurement of an out-of-plane circular photogalvanic current, the direction of which depends on the optical induction. Although the role of domain walls requires further investigation with local probes, the methodology demonstrated here can be applied to realize and control chiral electronic phases in other quantum materials,.