Chiral orbital current driven topological Hall effect in Mn3Si2Te6

Abstract

Chiral orbital current (COC) plays a crucial role in governing the magnetization and transport behaviour in the layered ferrimagnetic nodal-line semiconductor Mn3Si2Te6. Here, we observe that the topological Hall effect (THE), typically attributed to Berry curvature from chiral spin textures, originates from COC, which produces an emergent magnetic field for conduction electrons due to its real-space orbital textures. We find that the THE signal strengthens as we move down from bulk to nanoflakes, but tends to disappear with increasing current, along with the disappearance of the COC state. We also demonstrate a strong correlation between the colossal magnetoresistance (CMR) and the observed THE, suggesting that large Berry curvature and topological transport can arise purely from orbital degrees of freedom, providing a new platform for engineering dissipationless transport in 2D magnets.

Figures (4)

• Figure 1: (a) Temperature dependence of magnetization M(T) of bulk MST samples at B = 0.1 T along B $\|$ ab and B $\|$ c directions. Inset: Isothermal magnetization M(B) at T = 5 K for both B $||$ ab and B $||$ c. (b) Temperature dependence of the electrical resistivity of bulk MST. Inset: Magnetic field dependence of MR$\%$ at 5 K with B $\|$ c. (c) Hall resistivity curve at 5 K for bulk MST samples. (d) Hall resistivity curve at 5 K for the nanoflake MST device.
• Figure 2: The field dependence of Hall resistivity ($\mathrm{\rho_{xy}}$) at different temperatures for (a) Bulk and (b) Device of MST, respectively, along B $\|$ c directions. Hall resistivity curves at 5 K, fitted to extract the topological Hall contribution for (c) Bulk and (d) Device of MST, respectively. The black circles represent the raw $\mathrm{\rho_{xy}}$ data, and the red solid line represents the fitted curves. Contour plots of the THE contribution ($\mathrm{\rho_{xy}^{THE}}$) for (e) Bulk and (f) Device of MST, respectively, as a function of temperature and magnetic field.
• Figure 3: Contour plots of the THE amplitude ($\mathrm{\rho_{xy}^{THE}}$) for (a) - (e) Bulk and (f) - (j) Device, of MST, respectively, as a function of temperature and magnetic field for different applied currents.
• Figure 4: Temperature dependence of MR$\%$ and maximum relative topological Hall conductivity $[\mathrm{[\sigma_{xy}^{THE}/\sigma_{xy}]_{max}} (\%)]$ for (a) Bulk and (b) Device of MST, respectively. Current dependence of MR$\%$ and relative topological Hall conductivity $[\mathrm{[\sigma_{xy}^{THE}/\sigma_{xy}]_{max}} (\%)]$ for the device of MST at (c) 5 K and (d) 10 K, respectively. Arrows indicate the scale followed by the curves, respectively.