Fermi Surface, Electrical Resistivity and Magnetic Ordering of Antiferromagnetic Hexagonal FeGe

Nonrelativistic APW calculations of the electronic energy bands of hexagonal (B 35) iron monogermanide (FeGe) have recently been published [15]. The present work extends these to determine the Fermi surface, which is formed from four energy bands. Large portions of the Fermi surface will be destroyed or distorted by magnetic superzones at the onset of antiferromagnetic ordering (TN = 411 K). This is related to experimental resistivity measurements, which show a distinct anomaly at the Néel temperature. We find that "nesting" of Fermi hole and electron surfaces might give rise to a broad maximum in the generalized susceptibility around q = π/c. Further aspects of the role of the Fermi surface in magnetic ordering are briefly discussed.