Optical Response of a screw dislocated GaAs Quantum Wire: Temperature and Pressure Effects

We investigate the influence of a screw dislocation, characterized by the dislocation parameter, on the optical response of a parabolic GaAs cylindrical quantum wire under the combined effects of temperature, hydrostatic pressure, and the axial magnetic field. Using a torsion-modified metric together with pressure- and temperature-dependent material properties, namely the effective mass and dielectric permittivity, we obtain exact solutions of the Schr\"odinger equation in terms of Whittaker functions. The screw dislocation introduces a $k_z$-dependent coupling that breaks the symmetry between the angular momentum states $m$ and $-m$ and modifies the centrifugal term in the effective potential. Based on the resulting eigenstates, we evaluate the linear and third-order nonlinear optical absorption coefficients, as well as the corresponding refractive index changes, for the dipole-allowed transitions $m = 0 \to +1$ and $m = 0 \to -1$. Our results show that increasing the dislocation parameter produces a pronounced redshift and suppresses the resonance amplitude for the $m = 0 \to +1$ transition, whereas the $m = 0 \to -1$ transition exhibits a blueshift accompanied by peak enhancement. We further find that increasing temperature shifts the resonances toward higher photon energies and enhances their amplitudes, while hydrostatic pressure causes a redshift and reduces the peak intensity for both transitions. In addition, the magnetic field strengthens the optical response and induces a blueshift for the $m = 0 \to +1$ transition, whereas the opposite behavior is obtained for the $m = 0 \to -1$ transition. We have also examined the behavior of the refractive index changes, which exhibit analogous asymmetric dependence on the dislocation parameter.