BEGIN:VCALENDAR VERSION:2.0 PRODID:Data::ICal 0.22 BEGIN:VEVENT DESCRIPTION:Weigang Wang\, University of Arizona\n\n
Information technolo gy backed by sophisticated semiconductor devices have deeply changed our s ociety in the past two decades\, with AI-driven tools such as ChatGPT posi ted to bring even deeper impact. However\, in the physics governing device s behind most of these applications\, we have only utilized the charge car ried by electrons\, while ignoring the other inherent quantum property\, t he spin.  \;My research focuses on the understanding of the spin degre e of freedom of electrons at nanoscales. First I will give an introduction on a few key phenomena in the field of spintronics\, such as the coherent tunneling of spins by controlling the symmetry of the wavefunctions\, and the exchange scattering effect in materials with compensated magnetizatio n where the spins can be manipulated in the picosecond time scale. Then I will present in detail one of our research directions in which we attempt to control the order parameter of magnetic systems by using electric field s\, instead of magnetic fields or spin-polarized currents. Through the vol tage controlled magnetic anisotropy effect where the energy of the system can be modified by the redistribution of wavefunctions induced by external electric potentials\, a 100-fold reduction in switching current density h as been realized. We have demonstrated that both the magnetic anisotropy a nd saturation magnetization of a metallic ferromagnet can be controlled by voltage\, leading to a new method to modify the interlayer exchange coupl ing of the system\, directly verified by in-situ X-ray magnetic circular d ichroism experiment. In addition to the ferromagnetic order\, the antiferr omagnetic order can also be effectively manipulated by electric fields. Fi nally\, I will describe our recent effort to reduce the switching energy o f magnetic tunnel junctions. By controlling the spin-orbit interaction of the system using a remote doping technique\, we have achieved a record-low switching energy of ~3 fJ using sub-ns voltage pulses.
\n DTSTART:20230213T203000Z LOCATION:Monroe Hall\, Room 110 SUMMARY:Ultra-Low Energy Manipulation of Spin in Nanostructures END:VEVENT END:VCALENDAR