Visiting Student - XSD - Chang, Shih-Chao - 4.27.26

Argonne National Laboratory • Lemont, IL

23h • Onsite

About The Position

This project aims to investigate the nonequilibrium lattice dynamics and interfacial coupling in freestanding bilayer oxide systems, with a focus on SrTiO₃ (STO), PbZrO₃ (PZO), and their heterostructure (PZO/STO). By removing substrate clamping effects, freestanding architectures provide a unique platform to access intrinsic lattice responses, strain relaxation pathways, and emergent interfacial phenomena that are otherwise obscured in conventional thin films. The central objective of the research is to investigate how ultrafast stimuli can drive structural and polarization dynamics across coupled oxide layers, particularly in systems exhibiting competing ferroelectric and antiferroelectric phases. The experimental approach this project will use is time-resolved X-ray diffraction (TR-XRD). By employing pump–probe techniques with sub-nanosecond temporal resolution, TR-XRD enables direct tracking of lattice evolution following ultrafast excitation. This method provides access to transient changes in lattice constants, symmetry, and coherent phonon dynamics, allowing us to capture the real-time structural response of both individual layers and their interfaces. Special emphasis will be placed on identifying how interfacial coupling in PZO/STO heterostructures modifies energy dissipation pathways and structural relaxation dynamics. The freestanding geometry is expected to enhance strain-mediated effects and enable large-amplitude lattice motion, offering new insights into the coupling between mechanical, electronic, and polar degrees of freedom. Furthermore, the project will explore how defect distributions and stoichiometry variations influence ultrafast responses, linking materials synthesis conditions to dynamical functionality. The outcomes of this research will provide fundamental understanding of ultrafast phenomena in low-dimensional oxide systems and establish design principles for dynamically tunable materials. By integrating advanced synthesis, multimodal characterization, and state-of-the-art ultrafast X-ray techniques, this work aims to bridge the gap between static material properties and real-time functional behavior. Ultimately, the insights gained will contribute to the development of high-speed oxide electronics, optically controlled ferroelectric devices, and emergent quantum materials platforms.

Requirements

• Must be 18 years or older at the time the appointment begins.
• Currently enrolled in undergraduate or graduate studies at an accredited institution.
• Graduated from an accredited institution within the past 3 months; or Actively enrolled in a graduate program at an accredited institution.
• The entirety of the appointment must be conducted within the United States.

Nice To Haves

• Prior experience performing comprehensive structural and electronic characterization on PZO/STO freestanding films.
• Experience with X-ray diffraction (XRD) to determine crystal structure, phase purity, and strain states.
• Experience with X-ray absorption spectroscopy (XAS) to probe local electronic structure and cation valence states.
• Experience with scanning probe microscopy (SPM), including piezoresponse force microscopy (PFM), to map nanoscale polarization textures and domain configurations.
• Familiarity with pump–probe techniques with sub-nanosecond temporal resolution.

Responsibilities

• Investigate the nonequilibrium lattice dynamics and interfacial coupling in freestanding bilayer oxide systems.
• Investigate how ultrafast stimuli can drive structural and polarization dynamics across coupled oxide layers.
• Track lattice evolution following ultrafast excitation using time-resolved X-ray diffraction (TR-XRD).
• Identify how interfacial coupling in PZO/STO heterostructures modifies energy dissipation pathways and structural relaxation dynamics.
• Explore how defect distributions and stoichiometry variations influence ultrafast responses.

What This Job Offers

• Job Type: Full-time
• Career Level: Entry Level
• Education Level: No Education Listed