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2D‐Berry‐Curvature‐Driven Large Anomalous Hall Effect in Layered Topological Nodal‐Line MnAlGe
Author(s) -
Guin Satya N.,
Xu Qiunan,
Kumar Nitesh,
Kung HsiangHsi,
Dufresne Sydney,
Le Congcong,
Vir Praveen,
Michiardi Matteo,
Pedersen Tor,
Gorovikov Sergey,
Zhdanovich Sergey,
Manna Kaustuv,
Auffermann Gudrun,
Schnelle Walter,
Gooth Johannes,
Shekhar Chandra,
Damascelli Andrea,
Sun Yan,
Felser Claudia
Publication year - 2021
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.202006301
Subject(s) - berry connection and curvature , condensed matter physics , topology (electrical circuits) , ferromagnetism , materials science , fermi level , magnetization , hall effect , magnetism , geometric phase , physics , magnetic field , electron , quantum mechanics , mathematics , combinatorics
Abstract Topological magnets comprising 2D magnetic layers with Curie temperatures ( T C ) exceeding room temperature are key for dissipationless quantum transport devices. However, the identification of a material with 2D ferromagnetic planes that exhibits an out‐of‐plane‐magnetization remains a challenge. This study reports a ferromagnetic, topological, nodal‐line, and semimetal MnAlGe composed of square‐net Mn layers that are separated by nonmagnetic Al–Ge spacers. The 2D ferromagnetic Mn layers exhibit an out‐of‐plane magnetization below T C ≈ 503 K. Density functional calculations demonstrate that 2D arrays of Mn atoms control the electrical, magnetic, and therefore topological properties in MnAlGe. The unique 2D distribution of the Berry curvature resembles the 2D Fermi surface of the bands that form the topological nodal line near the Fermi energy. A large anomalous Hall conductivity of ≈700 S cm –1 is obtained at 2 K and related to this nodal‐line‐induced 2D Berry curvature distribution. The high transition temperature, large anisotropic out‐of‐plane magnetism, and natural heterostructure‐type atomic arrangements consisting of magnetic Mn and nonmagnetic Al/Ge elements render nodal‐line MnAlGe one of the few, unique, and layered topological ferromagnets that have ever been observed.