Weyl fermions are a recently discovered ingredient for correlated states of electronic matter. A key difficulty has been that real materials also contain non-Weyl quasiparticles, and disentangling the experimental signatures has proven challenging. Here we use magnetic fields up to 95 T to drive the Weyl semimetal TaAs far into its quantum limit, where only the purely chiral 0th Landau levels of the Weyl fermions are occupied. We find the electrical resistivity to be nearly independent of magnetic field up to 50 T: unusual for conventional metals but consistent with the chiral anomaly for Weyl fermions. Above 50 T we observe a two-order-of-magnitude increase in resistivity, indicating that a gap opens in the chiral Landau levels. Above 80 T we observe strong ultrasonic attenuation below 2 K, suggesting a mesoscopically textured state of matter. These results point the way to inducing new correlated states of matter in the quantum limit of Weyl semimetals.
Ramshaw BJ, Modic KA, Shekhter A, et al. Quantum limit transport and destruction of the Weyl nodes in TaAs. Nature Communications. 2018;9(1). doi:10.1038/s41467-018-04542-9
Ramshaw, B. J., Modic, K. A., Shekhter, A., Zhang, Y., Kim, E.-A., Moll, P. J. W., … McDonald, R. D. (2018). Quantum limit transport and destruction of the Weyl nodes in TaAs. Nature Communications. Springer Nature. https://doi.org/10.1038/s41467-018-04542-9
Ramshaw, B. J., Kimberly A Modic, Arkady Shekhter, Yi Zhang, Eun-Ah Kim, Philip J. W. Moll, Maja D. Bachmann, et al. “Quantum Limit Transport and Destruction of the Weyl Nodes in TaAs.” Nature Communications. Springer Nature, 2018. https://doi.org/10.1038/s41467-018-04542-9.
B. J. Ramshaw et al., “Quantum limit transport and destruction of the Weyl nodes in TaAs,” Nature Communications, vol. 9, no. 1. Springer Nature, 2018.
Ramshaw BJ, Modic KA, Shekhter A, Zhang Y, Kim E-A, Moll PJW, Bachmann MD, Chan MK, Betts JB, Balakirev F, Migliori A, Ghimire NJ, Bauer ED, Ronning F, McDonald RD. 2018. Quantum limit transport and destruction of the Weyl nodes in TaAs. Nature Communications. 9(1), 2217.
Ramshaw, B. J., et al. “Quantum Limit Transport and Destruction of the Weyl Nodes in TaAs.” Nature Communications, vol. 9, no. 1, 2217, Springer Nature, 2018, doi:10.1038/s41467-018-04542-9.
All files available under the following license(s):
Creative Commons Attribution 4.0 International Public License (CC-BY 4.0):
2018_NatureComm_Ramshaw.pdf 1.79 MB