Charge Transport, Spin Transport and Magneto-Optics of Solid-State Topological Memory Devices
- Author(s): BHOWMICK, TONMOY KUMAR
- Advisor(s): Lake, Roger K.
- et al.
Topological spin textures such as skyrmions are strong candidates for next-generation
storage units and spintronic devices. Skyrmions formed on the surface of Topological Insu-
lators (TIs) give rise to additional device functionalities. The skyrmion-TI heterostructure
system shows quantized topological Hall effect (QTHE) without any external magnetic eld.
This shows that the topological properties of the skyrmion spin texture can be imprinted
on the Dirac electrons of the topological insulator. We also predict such a skyrmion-TI
heterostructure will give rise to high gure-of-merit magneto-optic Kerr effects (MOKE).
Optical dielectric tensor elements are calculated using a tight-binding model and the Kubo
formula. We show that the Fermi level dependence of the MOKE signatures is distinct
for the different magnetic textures. Based on this, a skyrmion optical memory device is
proposed. Next, we investigate antiferromagnetic (AFM) skyrmion since it offers couple of
advantages in terms of speed and stability compared to its ferromagnetic counterpart. We
investigate how AFM skyrmions can be manipulated using temperature gradient to realize
novel spintronic device. The effect of temperature gradients on AFM skyrmion dynamics
is predicted using a numerical Landau Lifshitz Gilbert (LLG) model.