Hydrogen induces chiral conduction channels in the topological magnet

Chirality, a characteristic handedness that distinguishes 'left' from 'right', cuts widely across all of nature$^1$, from the structure of DNA$^2$ to opposite chirality of particles and antiparticles$^3$. In condensed matter chiral fermions have been identified in Weyl semimetals$^4$ through their unconventional electrodynamics arising from 'axial' charge imbalance between chiral Weyl nodes of topologically nontrivial electronic bands. Up to now it has been challenging or impossible to create transport channels of Weyl fermions in a single material that could be easily configured for advancing chiral logic or spintronics$^{5,6}$. Here we generate chirality-directed conduction channels in inversion-symmetric Weyl ferromagnet (FM) $MnSb_2Te_4$, emergent from a deep connection between chirality in reciprocal and real space. We alter the bandstructure on-demand with an intake and a subsequent release of ionic hydrogen ($H^+$) $-$ a process we show to induce the tilt and rotation of Weyl bands. The transformed Weyl FM states feature a doubled Curie temperature $\geq50K$ and an enhanced angular transport chirality synchronous with a rare field-antisymmetric longitudinal resistance $-$ a low-field tunable 'chiral switch' that roots in the interplay of Berry curvature$^7$, chiral anomaly$^8$ and hydrogen-engendered mutation of Weyl nodes.