Gate-Tunable Unconventional Unidirectional Magnetoresistance in Chiral Tellurium Nanosheets

In bulk Te, symmetry restricts the induced spin polarization to the chiral axis, allowing unidirectional magnetoresistance (UMR) only when the magnetic field is aligned with this direction. Here, we demonstrate an unconventional UMR in chiral Te nanosheets that emerges under a magnetic field transverse to the chiral axis.

The unconventional UMR exhibits nearly linear magnetic-field and current dependences and reverses sign with opposite crystal handedness, confirming its intrinsic chiral origin. First-principles calculations explain the unconventional UMR by out-of-plane spin polarization induced by symmetry reduction in Te nanosheets. Furthermore, electrostatic gating experiments demonstrate that the unconventional UMR is governed by the electronic structure near the Fermi level.