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Thermodynamic Signatures of Weyl Fermions in NbP

Cornell Affiliated Author(s)

Author

K. Modic
Tobias Meng
Filip Ronning
Eric Bauer
Philip Moll
B. Ramshaw

Abstract

We present a high magnetic field study of NbP—a member of the monopnictide Weyl semimetal (WSM) family. While the monoarsenides (NbAs and TaAs) have topologically distinct left and right-handed Weyl fermi surfaces, NbP is argued to be “topologically trivial†due to the fact that all pairs of Weyl nodes are encompassed by a single Fermi surface. We use torque magnetometry to measure the magnetic response of NbP up to 60 tesla and uncover a Berry paramagnetic response, characteristic of the topological Weyl nodes, across the entire field range. At the quantum limit B* (≈32 T), τ/B experiences a change in slope when the chemical potential enters the last Landau level. Our calculations confirm that this magnetic response arises from band topology of the Weyl pocket, even though the Fermi surface encompasses both Weyl nodes at zero magnetic field. We also find that the magnetic field pulls the chemical potential to the chiral n = 0 Landau level in the quantum limit, providing a disorder-free way of accessing chiral Weyl fermions in systems that are “not quite†WSMs in zero magnetic field. © 2019, The Author(s).

Date Published

Journal

Scientific Reports

Volume

9

Issue

1

URL

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85061588722&doi=10.1038%2fs41598-018-38161-7&partnerID=40&md5=0513eea9cd96808097c7ceb764e5854e

DOI

10.1038/s41598-018-38161-7

Group (Lab)

Brad Ramshaw Group

Funding Source

1752784
715730

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