My group explores new measurement approaches to unravel physical phenomena arising from the interactions between electrons in a variety of systems of reduced dimensionality. We have developed new scanning probe techniques: a scanning single electron transistor, capable of imaging fractional electronic charge, and a scanning spin quantum bit, capable of imaging weak magnetic fields with unprecedented sensitivity and resolution. We also investigate physics of interacting electrons in layered materials, hybrid topological superconductivity, and the use of localized electron spins in semiconductors for encoding quantum information.
An exciting current research thrust in my group is the development of new experimental techniques for probing magnetic states in materials using magnons (spin waves). We have succeeded in developing methods for the creation of coherent magnons and are now working on measurement schemes in which magnon propagation and scattering are used as a probe. We expect this novel toll to be capable of interrogating fundamental properties of important classes of quantum materials such as graphene, graphene bilayers, and stacks of transition metal dichalcogenides. Based on theoretical predictions, these materials should host exotic magnetic excitations that cannot be effectively probed using conventional experimental probes.
In parallel, we are exploring ways to create artificial topological superconductors hosting emergent Majorana fermions, which are of great interest for fault-tolerant quantum computation. We have developed a two-dimensional nano-engineered platform for realizing topological superconductivity, which offers great robustness and removes the need for fine tuning of materials’ properties. The elementary building block of this platform is a long Josephson junction consisting of two conventional superconducting electrodes separated by a semiconductor with strong spin-orbit interaction. Reaching the topological phase simply requires application of an in-plane magnetic field and tuning the phase difference across the junction. Further development of this platform should allow controlled creation and manipulation of Majorana fermions. Once fundamental properties of this system are understood, it will be used as a building block to create even more complex nano-engineered systems that either realize some of the important theoretical models or lead to entirely unexplored physics.
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Emergent Phenomena in Quantum Systems
Harvard University, Department of Physics