  Symmetry-protected edge states serve as direct evidence of nontrivial
electronic topology in atomically thin materials. Finding these states in
experimentally realizable single-phase materials presents a substantial
challenge for their use for both fundamental studies and developing functional
nanoscale devices. Here, we show the presence of robust edge states in
phosphorene and group-Va monolayers with puckered lattice structures. By
carefully analyzing the symmetry of the atomic sites and edge modes properties,
we demonstrate that these atomically thin two-dimensional (2D) materials
realize recently introduced obstructed atomic insulator states with partially
occupied edge modes. The obstructed edge modes attain a Rashba-type spin
splitting with Rashba parameter ($\alpha$) of 1.52 eV \r{A} for arsenene. Under
strain or doping effects, these obstructed insulators transition to a phase
with substantial spin-Berry curvature, yielding a double quantum spin Hall
state with a spin Hall conductivity of 4$\frac{e^2}{h}$. The experimental
availability of phosphorene and other group-Va materials featuring puckered
lattice structures could enable verification of obstructed atomic states and
enhanced spin-Berry curvature effects discussed in this study, offering the
potential for applications in topological electronic and spintronic devices.
