Determine the nature of the pressure-induced transition in Fe2TiSi

Determine whether the inflection point near −20 GPa in Fe2TiSi corresponds to an electronic topological transition, specifically a Lifshitz-type transition induced by pressure.

Background

The calculations show that tensile pressure reduces the Fe2TiSi band gap, which approaches closure below approximately −23 GPa, suggesting a possible semiconductor-to-metal transition. The total-energy and lattice-parameter behavior does not indicate a structural phase transition, while both the band-gap and lattice-parameter curves exhibit an inflection near −20 GPa.

Because the observed anomaly is not explained by a structural instability, the authors speculate that it may represent an electronic topological transition. Establishing whether the transition is genuinely Lifshitz-type would require analysis beyond the reported pressure-dependent band-gap calculations, such as tracking Fermi-surface topology and electronic band extrema.

References

Therefore, we speculate that the inflection point near -20 GPa could be some sort of electronic topological transition, such as a Lifshitz-type transition under pressure.

— First Principle Analysis of the Magnetism and Electronic Structure of Fe2XSi (X=Ti, V)  (2609.02800 - Kachooee et al., 2 Sep 2026) in Section 3.5, “Pressure Effect on the Band Gap of Fe2TiSi”