High-Throughput Chirality Identification of Chiral Fermion Enantiomers by Ultrafast Terahertz Emission Spectroscopy

Topological chiral semimetals possess nondegenerate chiral fermions dominated by large Chern numbers, making them an ideal material platform for quantum control of chirality degree of freedom. However, high-throughput chirality identification of a chiral enantiomer, which is the first and foremost basic characterization, is still lacking. In this work, we demonstrate that terahertz (THz) emission from ultrafast excited circular photogalvanic effects can be used to effectively identify the chirality of topological chiral semimetal. As demonstrated for the topological chiral semimetal RhSn, the emitted THz electric fields excited by certain circularly polarized ultrafast light pulses are reversed for the opposite enantiomer. By comparing the single-crystal X-ray diffraction results, we show that THz emission serves as a high-throughput, contactless, and nondestructive method for identifying the chirality of topological chiral semimetals. Our findings will facilitate and thus promote the study of topological chiral semimetals and further advance the quantum manipulation of the chirality degree of freedom in topological materials.