About

Robert Hovden is an Associate Professor at the University of Michigan in the Michigan Materials Science and Engineering department. He holds a B.Sc. in Physics from Georgia Institute of Technology obtained in 2007 and a Ph.D. in Applied Physics from Cornell University completed in 2014. His research focuses on materials science and engineering, with teaching responsibilities including courses such as MSE562 Electron Microscopy I and MSE465 Structural and Chemical Characterization of Materials. Further details about his research interests and contributions are not provided on the page.

Research topics

• Optics
• Physics
• Materials science
• Chemistry
• Chemical physics
• Nanotechnology
• Quantum mechanics
• Condensed matter physics
• Geometry
• Molecular physics
• Crystallography

Selected publications

• OpenChemistry/tomviz: Tomviz 2.3.1

  Zenodo (CERN European Organization for Nuclear Research) · 2026-05-19

  otherOpen access

  ParaView & Qt Upgraded to ParaView 6.0.0, then 6.1.0 Migrated to Qt 6 New Workflows (specific for HXN beamline at NSLS-II) PyXRF workflow with SID filtering, CSV logs, and separate environment support Ptychography workflow with probe phase output and pixel size reading New Operators Deconvolution/denoise with cancellation support Similarity metric, PSD, and FSC 1D metric operators PyStackReg image alignment Remove scalar arrays operator Multi-Array Support @apply_to_each_array decorator automatically applied to most operators Multi-array support for cross-correlation, reconstructions, tilt axis shift, pad, and circle mask Pipeline Improvements Optional breakpoints at each operator Insert operators before the selected operator Visualization & UI ModulePlot/LineView for table results with log scaling and CSV export ShiftRotationCenter widget with physical units Animation helper: slice module and "Export Movie" button Custom palette backgrounds, voxel sizes in properties panel Interface builder: enable_if/visible_if conditionals, "save file" option Build & Infrastructure GitHub Actions CI on Linux, macOS, and Windows C++20, pybind11 3.0.0, Python 3.12/3.13 support Pixi-based build environment, loguru for crash stack traces Bug Fixes Fixed crashes on exit, module load failures, and large volume integer overflows Fixed tomopy reconstruction, Python console loading, and state file save/load

  PublisherDOI

• Probing first-cycle electrochemical kinetics and discontinuities in NMC cathodes using single-particle electrochemistry

  ChemRxiv · 2026-05-21

  articleOpen access

  Polycrystalline NMC particles undergo intergranular cracking during cycling due to anisotropic volume expansion. These cracks facilitate electrolyte penetration into the particles, improving electrochemical kinetics. While cracking and electrolyte penetration are well established, their frequency and extent are poorly understood. Here, we use single-particle electrochemistry to study electrochemical kinetics during the first and second charge cycles of individual NMC622 cathode particles. We identified an average of 65 electrochemical discontinuities during the first charge, each corresponding to an abrupt increase in electrochemical surface area from intergranular cracking. Moreover, by quantifying the exchange current between the first and second cycle, we show that the surface area increases by a factor of 10-20 within individual battery particles. These findings highlight the distinct electrochemistry of NMC particles during the first cycle and, more broadly, enable the study of discrete, discontinuous events within individual battery particles.

  PublisherDOI

• Helium-Cooled Cryogenic STEM Imaging and Ptychography for Atomic-Scale Study of Low-Temperature Phases

  ArXiv.org · 2026-03-11

  articleOpen access

  Much of the exotic functionality of prime interest in quantum materials emerges from structural and electronic ground states that can only be accessed at cryogenic temperatures. Understanding device operation therefore requires structural characterization under the same low-temperature conditions at which these functional phases exist, as room-temperature measurements often probe a different structural state. Achieving atomic-resolution in scanning transmission electron microscopy imaging and particularly 4D-STEM electron ptychography at liquid helium temperature has remained extremely challenging because even small amounts of drift, vibration, and thermal instability associated with the cryogen can disrupt the stringent stability requirements of atomic-resolution STEM. In this work we demonstrate atomic-resolution STEM and multislice electron ptychography at temperatures as low as 20 K using a commercial helium cooled holder. We find that rapid scans and a multi-stage registration workflow are critical to reducing artifacts associated with cryogenic instability for atomic-resolution imaging, while for ptychography scan position correction including compensation for coupling between probe aberrations and position refinement is necessary for successful reconstructions. Together these results establish a pathway for reliable atomic-resolution STEM and ptychography at low temperature, enabling direct visualization of structural ground states relevant to quantum technology.

  PublisherOA PDF

• Helium-Cooled Cryogenic STEM Imaging and Ptychography for Atomic-Scale Study of Low-Temperature Phases

  arXiv (Cornell University) · 2026-03-11

  preprintOpen access

  Much of the exotic functionality of prime interest in quantum materials emerges from structural and electronic ground states that can only be accessed at cryogenic temperatures. Understanding device operation therefore requires structural characterization under the same low-temperature conditions at which these functional phases exist, as room-temperature measurements often probe a different structural state. Achieving atomic-resolution in scanning transmission electron microscopy imaging and particularly 4D-STEM electron ptychography at liquid helium temperature has remained extremely challenging because even small amounts of drift, vibration, and thermal instability associated with the cryogen can disrupt the stringent stability requirements of atomic-resolution STEM. In this work we demonstrate atomic-resolution STEM and multislice electron ptychography at temperatures as low as 20 K using a commercial helium cooled holder. We find that rapid scans and a multi-stage registration workflow are critical to reducing artifacts associated with cryogenic instability for atomic-resolution imaging, while for ptychography scan position correction including compensation for coupling between probe aberrations and position refinement is necessary for successful reconstructions. Together these results establish a pathway for reliable atomic-resolution STEM and ptychography at low temperature, enabling direct visualization of structural ground states relevant to quantum technology.

  PublisherDOI

• Strain mapping of three-dimensionally structured two-dimensional materials

  Science Advances · 2026-02-27

  articleOpen access

  Strain plays a crucial role in tuning materials’ properties, influencing their optical, electrical, and chemical performances. In two-dimensional (2D) materials, applied stress often induces out-of-plane deformation, resulting in a more intricate three-dimensional (3D) topography, where mapping the strain remains a challenge due to the limitations of conventional characterization techniques. In this work, we introduce BRIGHT (Bragg-Rod Informed, Gradient-based Height-mapping Technique), an integrated method for reconstructing both the topography and planar strain profile of 3D-structured 2D materials using nanobeam four-dimensional scanning transmission electron microscopy (4D-STEM). We apply BRIGHT to a MoS 2 -MoSe 2 transition metal dichalcogenide (TMD) lateral heterojunctions exhibiting built-in strain and out-of-plane ripples and show that varying heterojunction widths lead to distinct surface morphologies and corresponding changes in the planar strain distribution. These results establish a foundation for more effective strain engineering in 2D materials by accounting for out-of-plane structural features, thereby enabling more precise control of strain-dependent properties.

  PublisherDOI

• Melting of charge density waves in low dimensions

  Matter · 2026-03-04

  articleOpen accessSenior author
  PublisherDOI

• Tunable symmetry breaking in a hexagonal-stacked moiré magnet

  Nature Physics · 2026-04-29

  article
  PublisherDOI

• Emergent ferromagnetism and unusual irreversible magnetoresistance in an intercalated van der Waals antiferromagnet

  Proceedings of the National Academy of Sciences · 2026-01-21

  articleOpen access

  Orthorhombic air-stable two-dimensional (2D) antiferromagnet (AFM) CrSBr has attracted much research interest lately thanks to its rich magnetic behaviors together with its remarkable electronic, excitonic, and polaritonic properties. Here, we report a reliable electrochemical intercalation method by inserting large tetrabutylammonium (TBA + ) ions into CrSBr layers. Magnetically, such intercalation efficiently suppresses the interlayer AFM and induces a ferromagnetic (FM) order with a much-enhanced transition temperature up to 200 K, nearly 70 K higher than the AFM onset of 132 K in pristine CrSBr. Electronically, the TBA + intercalation not only increases the electric conductivity of CrSBr, which is further enhanced by magnetic fields, but also introduces a giant negative irreversible magnetoresistance. This work demonstrates the tunable magnetic and electronic properties of CrSBr as well as their interplay, paving the way for advanced spintronic and magnetic memory devices.

  PublisherOA PDFDOI

• Optimal 3D chemical imaging with multimodal electron tomography

  npj Computational Materials · 2025-08-25 · 1 citations

  articleOpen accessSenior author

  Abstract Accurate mapping of nanoscale chemistry in three dimensions (3D) has been a longstanding challenge. Modern electron microscopy provides chemical images by electron energy loss spectroscopy (EELS) and energy dispersive x-ray spectrometry (EDX) but requires high fluences that damage specimens. In 3D, the requirements are worse; electron tomography demands many high-fluence chemical maps for reconstruction, creating a tradeoff between resolution, accuracy, and sample survival. Fused multimodal electron tomography (MM-ET) alleviates this requirement by leveraging lower-fluence high-angle annular dark-field (HAADF) images alongside a few chemical maps to dramatically improve chemical resolution. Here, experimental and computational parameter space is systematically explored to determine when MM-ET performs best. Ideal imaging conditions balance sample survival with resolution and chemical specificity; we recommend a tilt range of at least ± 70 ∘ , acquiring 40 equally spaced HAADF projections (signal-to-noise > 10), and 7 EELS/EDX maps of each chemistry (signal-to-noise > 4).

  PublisherOA PDFDOI

• Chiral quantum magnets with optically and catalytically active spin ladders

  ArXiv.org · 2025-08-17

  preprintOpen access

  Chiral quantum magnets with spin-states separated by a large energy gap are technologically attractive but difficult to realize. Geometrically frustrated topological states with nanoscale chirality may offer a chemical pathway to such materials. However, room temperature spin misalignment, weakness of Dzyaloshinskii-Moriya interactions, and high energy requirements for lattice distortions set high physicochemical barriers for their realization. Here, we show that layered iron oxyhydroxides (LIOX) address these challenges due to chirality transfer from surface ligands into spin-states of dimerized FeO6 octahedra with zig-zag stacking. The intercalation of chiral amino acids induces angular displacements in the antiferromagnetic spin pairs with a helical coupling of magnetic moments along the screw axis of the zig-zag chains, or helical spin-ladders. Unlike other chiral magnets, the spin states in LIOX are chemically and optically accessible, they display strong optical resonances with helicity-matching photons and enable spin-selective charge transport. The static rather than dynamic polarization of spin ladders in LIOX makes them particularly suitable for catalysis. Room-temperature spin pairing, field-tunability, environmental robustness, and synthetic simplicity make LIOX and its intercalates a uniquely practical family of quantum magnets.

  PublisherOA PDFDOI

Frequent coauthors

• Suk Hyun Sung

  98 shared

• Lena F. Kourkoutis

  Cornell University

  82 shared

• Jonathan Schwartz

  Mayo Clinic in Arizona

  74 shared

• David A. Muller

  Cornell University

  71 shared

• Jiseok Gim

  University of Michigan–Ann Arbor

  52 shared

• Yuping Sun

  Hefei Institutes of Physical Science

  50 shared

• Yi Jiang

  Argonne National Laboratory

  44 shared

• John T. Heron

  University of Michigan–Ann Arbor

  37 shared

Education

• B.S., Physics

  Georgia Institute of Technology