Deans’ Summer Research Fellowship (DSRF) Story: Lang Ji

Lang was awarded the Deans' Summer Research Fellowship for summer 2025. Learn more about his time below.

Author: Lang Ji

What was your major research question for the DSRF project and where do you hope this project will go?

This project asks: How does ILG influence oxygen vacancy formation and carrier concentration in LaSrMnO₃/LaSrCrO₃ heterostructures, and how do these changes couple to their structural, magnetic, and transport responses? Ionic liquid gating (ILG) in transition metal oxides offers a reversible route to tune electronic and structural properties through electrostatic carrier modulation or oxygen vacancy formation. In manganite (LaSrMnO₃) and chromate (LaSrCrO₃) thin films, functional behaviors such as metal–insulator transitions, magnetism, and superconductivity are governed by charge, strain, and oxygen stoichiometry. ILG provides a way to directly manipulate these factors: oxygen vacancies in LaSrMnO₃ suppress ferromagnetism and metallicity, while charge redistribution in LaSrCrO₃ alters transport and magnetic states. To address this, I will study both single-layer and heterostructured films, using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transport measurements to disentangle electrostatic and ionic effects. The broader goal is to clarify ILG’s role as a control mechanism for correlated oxides. By establishing how ILG manipulates carrier density and lattice degrees of freedom, this work aims to advance strategies for engineering reconfigurable materials relevant to energy-efficient electronic, spintronic, and neuromorphic devices.

What challenges did you encounter during your research and how did you work through these difficulties?

Over the summer, heavy rain in Durham caused flooding in our lab, which disrupted the experimental schedule. Fortunately, the facilities have since been repaired and operations are returning to normal. As a result, we expect to resume and complete the necessary experiments this semester.

What sparked your interest in this field?

I love physics because it bridges theory to experiment so nicely. I chose to work in condense matter physics because there are a lot of involvement with experiments as an undergraduate student.

Curious about DSRF?

This project was made possible through the Deans’ Summer Research Fellowship (DSRF)—a unique opportunity for rising juniors and seniors in the Trinity College of Arts & Sciences to pursue funded summer research full-time!  

Effective this 2025-2026 Academic year, we are rebranding DSRF to be the Trinity Summer Undergraduate Mentored Research Fellowship (T-SUMR)! If you're pursuing graduation with distinction and are passionate about research, consider applying to T-SUMR in December of your Sophomore or Junior year.