  We investigate disordered-driven transitions between trivial and topological
insulator (TI) phases in two-dimensional (2D) systems. Our study primarily
focuses on the BHZ model with Anderson disorder, while other standard 2DTI
models exhibit equivalent features. The analysis is based on the local Chern
marker (LCM), a local quantity that allows for the characterization of
topological transitions in finite and disordered systems. Our simulations
indicate that disorder-driven trivial to topological insulator transitions are
nicely characterized by $\mathcal{C}_0$, the disorder averaged LCM near the
central cell of the system. We show that $\mathcal{C}_0$ is characterized by a
single-parameter scaling, namely, $\mathcal{C}_0(M, W, L) \equiv
\mathcal{C}_0(z)$ with $z = [W^\mu-W_c^\mu(M)]L$, where $M$ is the Dirac mass,
$W$ is the disorder strength and $L$ is the system size, while $W_c(M) \propto
\sqrt{M}$ and $\mu \approx 2$ stand for the critical disorder strength and
critical exponent, respectively. Our numerical results are in agreement with a
theoretical prediction based on a first-order Born approximation (1BA)
analysis. These observations lead us to speculate that the universal scaling
function we have found is rather general for amorphous and disorder-driven
topological phase transitions.
