Electronic structures and magnetism of LaFe2Ge2 and LaFe2Si2: First-principles studies

• Study the electronic and magnetic properties of LaFe2Ge2 and LaFe2Si2.
• Find LaFe2Ge2 and LaFe2Si2 share similar electronic structures and magnetism properties.
• The band structure and Fermi surfaces exhibit significantly three dimensional character and very similar in shape to that of YFe2Ge2.
• Both LaFe2Ge2 and LaFe2Si2 were suggested nearness to a magnetic quantum critical point (QCP).

Inspired by the recent discovery of superconductivity in YFe2Ge2, we report first-principles calculations on the electronic structure and magnetic properties of LaFe2Ge2 and LaFe2Si2. We found that LaFe2Ge2 and LaFe2Si2 share similar electronic structure and magnetism properties. In the nonmagnetic state, the density of states at the Fermi level are mostly derived from the dxy, dyz, and dzx orbits, just like the Fe-pnictide superconductors. The band structure and Fermi surfaces exhibit significantly three dimensional character. Our calculations indicate that the ground state of LaFe2Ge2 and LaFe2Si2 is the stripe antiferromagnetic configuration in the a-b plane and stacked antiparallel along the c-axis direction. The overestimate magnetic tendency within calculation indicates these systems nearness to a magnetic quantum critical point (QCP).