Oral Session 4
Tuesday, March 30, 2021 | 15:45-17:15 EDT | Go to About Oral Sessions to learn more about the session format.
Session Chair: Matthew Rosen (Mass General / Martinos Center for Biomedical Imaging, Harvard Medical School)
Invited Speakers & Abstracts
NMR/MRI Studies of Ion Transport and Dendrite Growth in All-Solid-State Batteries
Due to its non-invasive nature and sensitivity to local structures and dynamics, NMR has been instrumental to tackling many critical questions that cannot be addressed with other techniques. Two examples of such questions are ion transport and dendritic growth in solids, in particular, ion conductors. Although macroscopic behavior of these phenomena has been studied, the microscopic view, which is essential to guide material design, is often complex and elusive. Electrochemically-driven tracer-exchange NMR, combining isotope exchange induced by electric field gradient and high-resolution NMR, has demonstrated its efficacy in determining ion transport pathways and the origin of dendrite growth. In addition, in situ Li magnetic resonance imaging provides necessary spatial and temporal resolution for monitoring dendrite growth in real time.
Non-Hermitian dynamics of spin chains with loss and gain
We study the non-Hermitian dynamics of hybrid electron/nuclear spin systems in the simultaneous presence of electron spin pumping and spin-lattice relaxation. Focusing on periodic, one-dimensional chains, we find that by adjusting the electron spin pumping to a critical level, it is possible to steer the flow of nuclear polarization to create site-dependent distributions where either end of the array polarizes in opposite ways, irrespective of the initial state. By contrast, we show that ring-like patterns — where the limit nuclear polarization is uniform — exhibit a non-decaying nuclear spin current. Interestingly, cyclic magnetic field modulation can render these processes largely robust to defects in the chain, a response featuring some interesting similarities with recent findings in other non-Hermitian physical platforms.
Quantum Sensing of Quantum Materials
The magnetic fields generated by spins and currents provide a unique window into the physics of correlated-electron materials and devices. Proposed only a decade ago, magnetometry based on the electron spin of nitrogen-vacancy (NV) defects in diamond is emerging as a platform that is exceptionally suited for probing condensed matter systems: it can be operated from cryogenic temperatures to above room temperature, has a dynamic range spanning from DC to GHz, and allows sensor-sample distances as small as a few nanometers. As such, NV magnetometry provides access to static and dynamic magnetic and electronic phenomena with nanoscale spatial resolution. In this talk, I will review some of our recent work that uses NV center magnetometry to explore quantum matter.