Research

The past decade has witnessed a convergence of several paradigms in condensed matter physics (in particular, symmetry, topology and correlation) in bringing about theretofore unknown phases of matter--our research group is excited about searching for and establishing design principles of novel electronic phases at these crossroads in a broad class of "quantum materials". We study these materials in the single crystalline form and extract the nature of the phases these materials host using transport, thermodynamic and scattering probes. In the laboratory, we also apply a variety of fields as materials tuning parameters, including vectorial electric and magnetic fields, along with the tensorial strain field.

Below are a few topics we are currently interested in:

Electrons on flat bands

Flat bands are fascinating objects thanks to their massive quantum mechanical degeneracy--from this manifold of states numerous correlated and symmetry-breaking ground states can emerge. Like that flat bands can arise in moiré superlattices from a balance between intra- and inter-layer hopping, here we intend to similarly establish design principles for flat bands at the Fermi level in bulk crystalline materials, using their underlying lattice and orbital degrees of freedom as fundamental building blocks.

Tunable topology from frustration and correlation

Topological electronic states exhibit unique transport and electrodynamic responses robustly tied to their underlying topology. We would like to design highly tunable topological states in the context of competing phases in geometrically frustrated and/or strongly correlated electron systems; there the presence of multiple energy scales can potentially give rise to topological phase transitions extremely sensitive to external tuning parameters.

Dual role of strain as tuning parameter and probe

The ability to apply uni-axial strain in a quasi-continuous manner using piezoelectric devices not only allows the in-situ tuning of underlying materials, but also introduces various response functions of strain as new probes that inherit the spatial-symmetry properties of the former. We expect to exploit the dual role of strain as tuning parameter and probe to uncover novel electronic phases under induced lattice deformation. On the left we illustrate the example of the adiabatic elastocaloric effect, which probes the thermodynamic landscape of a given system under strain, along the isentropic lines.