We address the problem of magnetic field induced corner states in quantum spin Hall insulators beyond the particle hole symmetric limit. Starting from a realistic low-energy model for zinc-blende semiconductor quantum wells, we derive the effective edge Hamiltonian in the form of a Dirac Hamiltonian with two magnetic field dependent mass terms, whose structure depends on the crystallographic orientation of the edge and of the magnetic-field orientation. Our analytical results show that magnetic field induced corner states are most naturally understood as in-gap bound states of the effective edge theory, controlled by the relative configuration of the edge mass vectors rather than, in general, as higher-order topological corner modes protected by a stable bulk invariant. We demonstrate that, although mirror-graded winding numbers can be defined and quantized for certain crystallographic configurations, the existence of magnetic field induced corner states is not restricted to regimes in which these bulk invariants are well defined. Finally, we argue that even without higher-order topological protection these corner states may remain spectrally robust under weak perturbations as isolated in-gap quasiparticle excitations.

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• Quantum spin Hall effect
• Quantum wells
• Topological insulators
• Topological materials