The  paper of  the  month,  chosen  by  the Editor-in-Chief,  is  "On Weyl Nodes in Ferromagnetic Weyl Semimetal"   by  U.P. Tyagi and P. Goswami;

DOI: 10.12693/APhysPolA.144.197

Crystals with non-trivial topological properties are one of the most interesting and intensively studied systems in condensed matter physics. Weyl semimetals are one of them. They are not only interesting from the point of view of basic physics but also it is expected that they can be used in fast electronics. In the present paper a simple model of ferromagnetic Weyl semimetal is studied. In spite of being simple, the model takes into account all essential ingredients of such systems: the tunneling effect, exchange field leading to ferromagnetism, chirality of the Weyl nodes and the shift of the nodes. The presence of the Weyl points of opposite chirality has been shown in the band structure. Also the Berry curvature and the anomalous Hall conductivity have been found. In addition, it has been shown that interaction with light can change the topological states, this can even lead to emergence of a novel phase with broken time reversal symmetry. This relatively simple model shows a variety of nontrivial properties that can exist in crystals. The present paper significantly broadens our knowledge about these important modern materials.

The Editor-in-Chief