Topological phase engineering of rutile GeO2 with strain

• Published in: Physics letters. A 2024-12, Vol.527, p.129989, Article 129989
• Main Authors: Guo, Shuaihui, Wang, Xiaoxiong
• Format: Article
• Language: English
• Subjects: 3D Dirac semimetal; GeO2; Nodal-line semimetal; Strain; Topological phase engineering
• ISSN: 0375-9601
• DOI: 10.1016/j.physleta.2024.129989

Nodal-line semimetals serve as the parent phase for various topological states. By manipulating spin-orbit coupling (SOC), time-reversal symmetry, or spatial inversion symmetry, a Dirac nodal-line semimetal can transition into a 3D Dirac semimetal, Weyl semimetal, or topological insulator. In this study, we present the topological phase engineering of rutile GeO2 under strain through first-principles calculations. Without considering SOC effect, applying tensile strain to GeO2 induces a transformation from a trivial insulator to a Dirac nodal-line semimetal, characterized by two orthogonal and interconnected Dirac nodal rings protected by mirror symmetry. When SOC is taken into account, the band degeneracy persists only at two points, resulting in a 3D Dirac semimetal. Nonetheless, due to the negligible strength of SOC in GeO2, its nodal-line semimetal properties remain largely intact even after including SOC effects. Our findings provide valuable insights for the topological phase engineering and potential spintronics applications of GeO2. •A nodal-line semimetal state is realized by applying a tensile strain to rutile GeO2 when the SOC effect is ignored.•The nodal lines consist of two interconnected, orthogonal nodal rings protected by mirror symmetry.•When the SOC effect is counted in, the nodal lines degrade into degenerate points and it becomes a Dirac semimetal.•The gap induced by SOC effect is negligible in GeO2, hence GeO2 is an ideal candidate for nodal-line semimetal study.