Magnetoresistance in Tellurium

Tellurium (Te) possesses a simple crystal structure with three tellurium atoms forming a spiral-shaped covalently bonded atomic chain in each unit cell. This structure makes Te a chiral material, whose handedness is determined by the helicity of the atomic chain. Te also has very low resistivity compared to chiral polymers, making it stand out as a compelling inorganic chiral material for exploring the interplay between structural chirality, strong spin-orbit coupling and charge transport. Due to its chiral structure, Te has both spatial inversion and mirror symmetry broken, resulting in a radial spin texture at the Fermi level. Thus, when a charge current is applied along the chirality direction, the Fermi surface will be distorted, and spins of electrons will be polarized either parallel or anti-parallel to the current direction depending on the handedness of the Te chirality. We are studying chirality-induced spin polarizations from the magnetoresistances of Te flakes. To be more specific, we applied a current along the chiral axis of Te and measured the longitudinal resistance of Te under different magnetic fields strengths and field directions with respect to the current directions. We observed unidirectional magnetoresistance when the field is along the current (and the chiral axis direction), which increased with the magnetic field. It showed opposite behaviors for Te flakes with opposite chiralities. We attribute the field-dependent unidirectional magnetoresistance to the spins polarized along the chiral axis.