Real-space imaging and control of chiral anomaly induced current at room temperature in topological Dirac semimetal.

Park, Byung Cheol; Ha, Taewoo; Sim, Kyung Ik; Jung, Taek Sun; Kim, Jae Hoon; Kim, Yeongkwan; Lee, Young Hee; Kim, Teun-Teun et al. · Sci Adv · 2022

basic_science · Level V

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Abstract

Chiral fermions (CFs) in condensed matters, distinguished by right (+) or left (-) handedness, hold a promise for emergent quantum devices. Although a chiral anomaly induced current, <b><i>J</i></b><sub>chiral</sub> = <b><i>J</i></b>(+) - <b><i>J</i></b>(-), occurs in Weyl semimetals due to the charge imbalance of the CFs, monitoring spatial flow and temporal dynamics of <b><i>J</i></b><sub>chiral</sub> has not been demonstrated yet. Here, we report real-space imaging and control of <b><i>J</i></b><sub>chiral</sub> on the topological Dirac semimetal KZnBi at room temperature (RT) by near-field terahertz (THz) spectroscopy, establishing a relation for an electromagnetic control of <b><i>J</i></b><sub>chiral</sub>. In THz electric and external magnetic fields, we visualize a spatial flow of coherent <b><i>J</i></b><sub>chiral</sub> in macroscopic length scale and monitor its temporal dynamics in picosecond time scale, revealing its ultralong transport length around 100 micrometers. Such coherent <b><i>J</i></b><sub>chiral</sub> is further found to be controlled according to field directions, suggesting the feasibility of information science with topological Dirac semimetals at RT.