Determine deformation potentials of PtSe₂

Determine the deformation potentials of PtSe₂, including their effects on the Fermi velocities and band-inversion parameter in the strain-dependent three-dimensional Bernevig–Hughes–Zhang Hamiltonian, in order to model the strain evolution of the circular photon-drag photocurrent more accurately.

Background

The paper models strain phenomenologically by modifying only the band-inversion parameter (or mass gap) according to M(ε) = M₀ + Λε. The authors note that strain could also anisotropically modify the Fermi velocities through lattice distortions and the Poisson effect, but these deformation potentials have not been established for PtSe₂. Determining them would enable a more physically complete description of the strain-dependent circular photon-drag response and could produce the nonmonotonic behavior observed experimentally.

References

While strain can also theoretically introduce anisotropic scaling to the Fermi velocities ($A_x, A_y, A_z$) due to lattice distortions and the Poisson effect, the current numerical implementation purely focuses on the lowest order impact of strain to the Hamiltonian, as deformation potentials are unknown for PtSe$_2$.

— Strain control of mid-IR spectroscopic nonlinear photocurrents in PtSe$_2$  (2608.16629 - Gerlei et al., 17 Aug 2026) in Supplementary Text, subsection “Strain Implementation”