Pressure driven Weyl-topological insulator phase transition in Weyl semimetal SrSi2

Using DFT-based first-principles calculations, we demonstrate the tuning of the electronic structure of Weyl semimetal SrSi2 via external uniaxial strain. The uniaxial strain facilitates the opening of bandgap along Γ-X direction and subsequent band inversion between Si p and Sr d orbitals. Z2 invariants and surface states reveal conclusively that SrSi2 under uniaxial strain is a strong topological insulator. Hence, uniaxial strain drives the semimetallic SrSi2 into fully gapped topological insulating state depicting a semimetal to topological insulator phase transition. Our results highlight the suitability of uniaxial strain to gain control over the topological phase transitions and topological states in SrSi2.