Transport chirality generated by a tunable tilt of Weyl nodes in a van der Waals topological magnet

Chirality — a characteristic handedness that distinguishes ‘left’ from ‘right’—is a fundamental property of quantum particles under broken symmetry intimately connected to their spins. Chiral fermions have been identified in Weyl semimetals through their unique electrodynamics arising from ‘axial’ charge imbalance between pairs of chiral Weyl nodes—the topologically protected ‘relativistic’ crossings of electronic bands. Chiral magnetotransport phenomena critically depend on the details of electronic band structure. However, the putative emergence of chiral electronic channels through shape altering of Weyl nodes is yet to be revealed. Here, we detect chirality-endowed linear conduction channels promoted by a tilt of Weyl bands in inversion-symmetric Weyl ferromagnet MnSb₂Te₄. The tuning of Weyl nodes is controlled with ionic hydrogen, which heals the system’s (Mn-Te) bond disorder and lowers the internode scattering. The reshaped Weyl states feature a doubled Curie temperature  ≳50 K and a strong angular transport chirality synchronous with a rare field-antisymmetric longitudinal resistance—a low-field tunable ‘chiral switch’ that is rooted in the interplay of Berry curvature, chiral anomaly and a hydrogen-mediated form of Weyl nodes.