Entela Buzi | Searcharxiv

arXiv2026

Hydrogen-induced modification of the local charge density in MnSb$_2$Te$_4$

We investigate the effects of ionic hydrogen (H$^+$) intake on the occupied and unoccupied states of MnSb$_2$Te$_4$, a van der Waals magnetic material. Using angle-resolved photoemission spectroscopy (ARPES) and time-resolved ARPES, combined with resonant and core level photoemission, we reveal that hydrogen binds near specific lattice sites, locally redistributing charge density and reshaping the valence band spectral weight. While the band gap and picosecond carrier dynamics show only minor changes upon hydrogenation, the conduction band exhibits a striking stoichiometry-dependent response. These findings indicate that hydrogen interacts strongly with the intrinsic defects in the lattice, acting as a selective dopant in MnSb$_2$Te$_4$. Our work provides a spectroscopic basis for using hydrogen as a tool for the control of the electronic and magnetic properties in layered 2D materials.

cond-mat.mtrl-sci↗

arXiv2023

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.

cond-mat.mtrl-sci↗