Speaker: Dr. Ramakrishna Podila (Clemson University)

Place: Natural Sciences Building, Room 112 

Title:

Disorder and interfaces in energy materials: from quantum localization to machine-learned thermal transport

Abstract:

Quantum interference in randomly disordered systems can lead to localization phenomena that fundamentally reshape electronic and thermal transport, offering new opportunities for energy applications. In this talk, I will discuss our recent work exploring Anderson localization and its impact on thermoelectric transport in defect-engineered graphene.

Controlled disorder is introduced in graphene through ion irradiation, allowing the inter-defect spacing to be systematically tuned and quantified using Raman spectroscopy. Electrical transport, thermopower measurements, and tight-binding simulations reveal the emergence of quantum interference–induced localization as the defect spacing approaches a critical threshold. Near this regime, ultrafast reflectance shows that carrier relaxation times peak and electrical resistivity exhibits signatures of hopping-dominated transport.

Remarkably, the localization regime also produces a pronounced enhancement in thermoelectric properties. Temperature-dependent measurements show that both the power factor and the thermoelectric figure of merit reach maxima near the critical defect spacing, providing experimental evidence that disorder-driven localization can enhance thermoelectric performance through energy filtering near mobility edges.

I will conclude by discussing how physics-informed machine learning approaches are being explored in measuring thermal transport properties in composite materials . Together, these studies illustrate how disorder, quantum interference, and data-driven approaches can be combined to understand and engineer transport in energy materials.