What we study

Research

Archana Raja leads an independent research program at the Molecular Foundry and the Kavli Energy NanoScience Institute at Lawrence Berkeley National Laboratory. Her group has pioneered the use of photons and electrons to image excitations at the interfaces of low-dimensional materials with nanometer spatial and ultrafast temporal resolution. She also co-leads multi-institution efforts that combine this experimental expertise with AI to discover new functionality in quantum materials and their heterostructures.

New directions

AI for Scientific Discovery in Quantum Materials

AI extends this experimental approach. As multimodal datasets grow richer, the challenge shifts from acquiring complementary measurements to interpreting them together and deciding what to measure next, a choice that matters because each measurement is costly and time-consuming. Raja co-leads three multi-institution programs that build AI-driven, closed-loop workflows connecting theory, simulation and experiment.

  • Co-PI & Project Integration Officer

    LEAP

    Low-Energy, AI-Informed Phase Transitions · University of California AI Science at Scale initiative

    Building AI co-scientists that find topological materials for energy-efficient electronics.

    • LEAP-Bench, the first benchmark that tests whether AI agents can reason from raw instrument data to scientific conclusions across multiple measurement modalities.
    • Struct-R1, an agentic framework for materials structure search with multi-fidelity measurements.
    • TritonDFT: leading deployment of agentic DFT workflows across the collaboration.

  • Co-PI · LBNL lead

    Genesis CASCADE

    DOE Genesis Mission

    An AI-driven, closed-loop workflow that bridges atomic-scale defect physics, photonic simulations and experimental measurements to accelerate the design of quantum materials and devices.

    With UC Irvine, ESnet and industry partner Single Quantum.

  • Co-PI

    AlphaFold for Microelectronics

    DOE Genesis Mission

    Generating high-throughput, correlated optical and structural datasets on ferroelectric HZO and 2D MoS₂ to train AI models for microelectronics materials discovery.

Experimental foundations

Her team pairs optical spectroscopy and microscopy with ultrafast electron diffraction and electron energy-loss spectroscopy to study interfaces as they really are, complete with defects, strain, disorder, and atomic reconstruction. Through the Molecular Foundry, she also supports a national and international user community, helping researchers apply these techniques to their own scientific questions.

Ultrafast & Ultrasmall Imaging of 2D Heterostructures

Combining these probes produced the first sub-nanometer imaging of excitons within a single moiré unit cell and revealed how ultrafast charge transfer across a 2D interface deposits energy into the lattice.

  • Moiré excitons at sub-nm resolution

    First sub-nanometer imaging of moiré excitons, using correlated optical and low-loss electron energy-loss spectroscopy.

    Science 2022

  • Energy transport at 2D interfaces

    Discovered an electron–phonon mediated energy-transport mechanism unique to 2D semiconductor interfaces, using ultrafast electron diffraction.

    Nature Nanotechnology 2023

  • A dynamic moiré potential

    Revealed the dynamic nature of the moiré potential through measurements of anomalous interlayer exciton transport.

    ACS Nano 2024

  • Cathodoluminescence of buried interfaces

    Determined how hBN encapsulation sets the spatial resolution of cathodoluminescence microscopy, and how to design heterostructures around it.

    Nanoscale 2022

Dielectric Screening in 2D Materials

Earlier in her career, Raja showed that an atomically thin semiconductor responds to its surroundings much like a molecule in a solvent, so its band gap can be tuned through the dielectric environment.

  • Coulomb engineering of the bandgap

    First demonstration of tuning the bandgap of a 2D semiconductor through its dielectric environment.

    Nature Communications 2017

  • Dielectric disorder

    Discovered a new form of electronic disorder arising from local fluctuations in the dielectric environment.

    Nature Nanotechnology 2019

  • Rigid band shifts

    Correlated optical spectroscopy with angle-resolved photoemission to reveal rigid band shifts from environmental screening.

    Physical Review Letters 2019

  • Screening vs. dissipation in energy transfer

    Clarified the competition between dielectric screening and dissipation in energy transfer from quantum dots to 2D materials.

    Nano Letters 2016

  • Screening and exciton–phonon scattering

    Delineated the role of screening in exciton–phonon scattering, linewidths and coherence lifetimes in transition metal dichalcogenides.

    Nano Letters 2018; Nature Communications 2016

Full list on the publications page.