The concept of the chiral gauge field (CGF), originally developed in theoretical particle physics, has now emerged in condensed matter systems in materials known as Weyl semimetals. In general, Weyl semimetals emerge from Dirac semimetals when time-reversal or spatial-inversion symmetries are broken. Recently, it has gained a growing interest to manipulate such topological states of matter by implementing the CGF by shining light to materials. Here we have demonstrated the emergence of CGF in a massive 3D Dirac electron system in the paramagnetic phase of Co3Sn2S2, which exhibits a ferromagnetic Weyl semimetal phase at low temperatures. We first show theoretically that the illumination of circularly polarized light implements the CGF in the paramagnetic state of Co3Sn2S2 and gives rise to a topological Weyl state, which can be realized only in the nonequilibrium state. Then we demonstrated that the presence of light-induced CGF through the observation of light-induced anomalous Hall effect, the behavior of which quantitatively agrees with the calculation from the Floquet theory. The light-induced AHE manifests the Berry curvature which becomes nonzero as the bands split due to the light-induced CGF. Our demonstration paves a new pathway for ultrafast manipulation of topological phases in 3D Dirac semimetals and for further exploring new quantum matter phases which can be only achieved by light.

中文翻译：

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大规模 3D 狄拉克电子系统中的光诱导手征规范场

手性规范场 (CGF) 的概念最初是在理论粒子物理学中发展起来的，现在已经出现在被称为外尔半金属的材料中的凝聚态系统中。一般来说，当时间反转或空间反转对称性被破坏时，外尔半金属会从狄拉克半金属中出现。最近，通过向材料照射光来实现 CGF 来操纵这种拓扑状态的物质引起了越来越多的兴趣。在这里，我们已经证明了 CGF 在 Co3Sn2S2 顺磁性相中的大质量 3D Dirac 电子系统中的出现，其在低温下表现出铁磁性 Weyl 半金属相。我们首先从理论上证明，圆偏振光的照射在 Co3Sn2S2 的顺磁性状态下实现了 CGF，并产生了拓扑 Weyl 状态，这只能在非平衡状态下实现。然后我们通过观察光诱导的异常霍尔效应证明了光诱导CGF的存在，其行为在数量上与Floquet理论的计算一致。光诱导的 AHE 表现出贝里曲率，由于光诱导的 CGF，当条带分裂时，该曲率变为非零。我们的演示为超快操纵 3D 狄拉克半金属中的拓扑相以及进一步探索只能通过光实现的新量子物质相铺平了一条新途径。光诱导的 AHE 表现出贝里曲率，由于光诱导的 CGF，当条带分裂时，该曲率变为非零。我们的演示为超快操纵 3D 狄拉克半金属中的拓扑相以及进一步探索只能通过光实现的新量子物质相铺平了一条新途径。光诱导的 AHE 表现出贝里曲率，由于光诱导的 CGF，当条带分裂时，该曲率变为非零。我们的演示为超快操纵 3D 狄拉克半金属中的拓扑相以及进一步探索只能通过光实现的新量子物质相铺平了一条新途径。