Spring 2022

A Pitt Chem Seminar

Abstract: Two topics will be covered in the general area of tunneling microscopy: looking at surface dynamics of glasses on a millisecond to hour scale, and excited state dynamics of nanomaterials on the sub-picosecond to nanosecond scale, both with sub-nm resolution. The technique of “SMA-STM” works by shining modulated light on a sample and detecting the resulting change in electron density with an STM tip, which also enhances the evanescent light wave that excites the sample. I’ll show that we can build energy landscapes of glass...

A CMU-Pitt Colloquium

Abstract: Electrons inside matter can behave as complex particles that do not exist in the Standard Model. These seemingly impossible effects are examples of emergent phenomena—that is, unexpected collective behavior—of electrons in quantum materials. The discovery and characterization of new emergent phenomena in quantum materials not only expand the boundary of our knowledge, but also provide unique opportunities for future quantum technologies. However, these effects often manifest in subtle ways, and thus detecting them requires...

A CMU-Pitt Colloquium

Abstract: Quantum materials host exotic states of matter with unique macroscopic phenomena, ranging from various correlated electron states to topological orders. The ability to manipulate and probe their emergent behavior with nanoscale precision is at the forefront of condensed matter research and underlies the future progress of new electronic and photonic technologies. Polaritonic platforms utilizing hybrid light-matter excitations with extreme light confinement enable a unique form of experimental inquiry into the...

A CMU-Pitt Colloquium

Abstract: With the advancements in quantum materials research, the emergent quantum many-body phenomena, such as competing orders, topological order and fractionalization, can be realized in much more controllable ways. 

However, resolving them experimentally can be challenging. In this talk, I will tell two stories of understanding the emergent phenomena in quantum materials, with setups both in and out of equilibrium. First, I will discuss our theory of the charge orders in recently extensively studied Vanadium based kagomé...

A CMU-PITT Colloquium

Abstract: Quantum materials provide an exciting platform to realize emergent phenomena and topological properties in condensed matter systems. Our ability to synthesize these materials with atomic precision enables us to rationally design quantum structures with tailored properties. In this talk, I will provide examples of such an approach using thin film synthesis by molecular-beam epitaxy that allows access to tuning parameters, such as, interfacial engineering and dimensional confinement, and the creation of artificial...

A CMU-PITT Colloquium

Abstract: The emergence of the two-dimensional (2D) transition metal dichalcogenides (TMDCs) ushers in a new era of light-matter interaction, offering exciting opportunities in quantum information science (QIS). In monolayer TMDCs, the reduced screening enhances the Coulomb interaction and gives rise to strongly bound excitons with the binding energy of hundreds of meV. In addition, the excitons in TMDCs possess a new quantum degree of freedom, valley-spin, which is promising for quantum information processing and can be accessed...