Physics & Astrophysics Colloquium: Dr. Shan Wu, Lawrence Berkeley National Lab


Location: 118 Nieuwland Science Hall (View on map )

Wu Shan

Magnetic resistance switching material

Dr. Shan Wu
Postdoctoral Fellow
Lawrence Berkeley National Lab

A quantum material is a complex system in which electrons interact strongly and collaboratively. As such, quantum mechanics plays a dominant role in the versatile materials that allow us to explore emergent quantum phenomena as well as their potential applications in future technologies. In recent decades, the emergent quantum materials embrace exotic material properties that demonstrate the significance of interplay among multiple dimensions in the system, for example the interwinted electronic orders in the high-temperature superconductors. These exotic properties can be harvested into applications for the next-generation quantum technologies. Antiferromagnetic (AFM) spintronics is one of among the promising quantum technologies, which realize the manipulation of spin-transport in antiferromagnets for memory devices.  Their macroscopically zero net moment and ultrafast spin dynamics allow the storage and transfer of information to be more closed packed and faster compared to their ferromagnetic counterparts. Recently, the intercalated transition metal dichalcogenide (TMD) antiferromagnet Fe1/3+δNbS2 has shown relevant spintronic features, namely, resistance switching.  Here, I will present our discovery of highly tunable antiferromagnetic orders and discuss how they relate to the observed resistance switching in this material.  With materials synthesis and characterizations, we perform single-crystal neutron diffraction measurement on a series of single crystals with subtle changes of the Fe ratio. Surprisingly, we observe a rapid change of magnetically long-ranged ordered states as the Fe ratio varies from under-intercalated (δ~-0.01) to over-intercalated (δ~0.01) samples. The rapid change of the magnetic states underlies the sensitive switching behaviors, providing crucial insights on the magnetic ground states that form the basis for understanding the fascinating spintronic behavior. I will also talk a bit about future opportunities as part of the exploration of the next-generation spintronic materials.

[Ref] S. Wu  et. al. Phys. Rev. X 12, 021003 (2022)