Emergence of Fermi arcs due to magnetic splitting in an antiferromagnet
Unconventional Fermi surface generation
a, Fermi surface map near Γ for several temperatures below and above TN. Black arrows mark area where surface state appears just below TN. Red and blue arrows point to split hole- and electron-like Fermi arcs/pockets, respectively. b, Band dispersion along cuts marked by the red dashed line in the bottom panel in a.
Fermi surfaces play an important role in controlling the electronic, transport and thermodynamic properties of materials. As the Fermi surface consists of closed contours in the momentum space for well-defined energy bands, disconnected sections known as Fermi arcs can be signatures of unusual electronic states, such as a pseudogap. Another way to obtain Fermi arcs is to break either the time-reversal symmetry or the inversion symmetry of a three-dimensional Dirac semimetal, which results in formation of pairs of Weyl nodes that have opposite chirality, and their projections are connected by Fermi arcs at the bulk boundary. We find that NdBi generates a pair of Fermi surfaces with opposite curvature upon crossing the phase transition into the anti-ferromagnetic regime. The opposite curvature that follows the order parameter is unusual, thereby differing from previous theoretically considered and experimentally reported cases of magnetic splitting, such as traditional Zeeman and Rashba, in which the curvature of the bands is preserved. As a result, out findings demonstrate a type of magnetic band splitting in the presence of a long-range antiferromagnetic order that is not readily explained by existing theoretical ideas.Emergence of Fermi arcs due to magnetic splitting in an antiferromagnet , Benjamin Schrunk, Yevhen Kushnirenko, Brinda Kuthanazhi, Junyeong Ahn, Lin-Lin Wang, Evan O’Leary, Kyungchan Lee, Andrew Eaton, Alexander Fedorov, Rui Lou, Vladimir Voroshnin, Oliver J. Clark, Jamie Sánchez-Barriga, Sergey L. Bud’ko,Robert-Jan Slager, Paul C. Canfield and Adam Kaminski, Nature 603, 610 (2022).