Nonlinear optical control of chiral charge pumping in a topological Weyl semimetal
- Columbia Univ., New York, NY (United States); OSTI
- Sharif University of Technology, Tehran (Iran)
- Univ. of Maryland, College Park, MD (United States); 4Universit¨at Duisburg-Essen, Duisburg (Germany)
- Univ. of Maryland, College Park, MD (United States); Science Systems and Applications, Inc. Lanham, MD (United States)
- Univ. of California, Los Angeles, CA (United States)
- Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany)
- Columbia Univ., New York, NY (United States)
- Univ. of Maryland, College Park, MD (United States)
Solids with topologically robust electronic states exhibit unusual electronic and optical properties that do not exist in other materials. A particularly interesting example is chiral charge pumping, the so-called chiral anomaly, in recently discovered topological Weyl semimetals, where simultaneous application of parallel DC electric and magnetic fields creates an imbalance in the number of carriers of opposite topological charge (chirality). Here, using time-resolved terahertz measurements on the Weyl semimetal TaAs in a magnetic field, we optically interrogate the chiral anomaly by dynamically pumping the chiral charges and monitoring their subsequent relaxation of the nonequilibrium state. Theory based on Boltzmann transport shows that the observed effects originate from an optical nonlinearity in the chiral charge pumping process. Our measurements reveal that the nonequilibrium chiral excitation relaxation time is much greater than 1 ns. The observation of terahertz-controlled chiral carriers with long coherence times and topological protection suggests the application of Weyl semimetals for quantum optoelectronic technology.
- Research Organization:
- University of Maryland, College Park, MD (United States); University of California, Los Angeles, CA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC)
- Grant/Contract Number:
- SC0005436; SC0011978
- OSTI ID:
- 1850939
- Journal Information:
- Physical Review. B, Journal Name: Physical Review. B Journal Issue: 24 Vol. 102; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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