  We propose a general and tunable platform to realize high-density arrays of
quantum spin-valley Hall kink (QSVHK) states with spin-valley-momentum locking
based on a two-dimensional hexagonal topological insulator. Through the
analysis of Berry curvature and topological charge, the QSVHK states are found
to be topologically protected by the valley-inversion and time-reversal
symmetries. Remarkably, the conductance of QSVHK states remains quantized
against either nonmagnetic or long-range magnetic disorder, verified by the
Green function calculations. Based on first-principles results, we show that
QSVHK states, protected with a gap up to 287 meV, can be realized in bismuthene
by alloy engineering, surface functionalization, or electric field, supporting
non-volatile applications of spin-valley filters, valves, and waveguides even
at room temperature.
