About

Professor Miaomiao (Mia) Jin is an Assistant Professor in the Department of Nuclear Engineering at Penn State University. She completed her Ph.D. in Nuclear Science and Engineering at the Massachusetts Institute of Technology in June 2019, with a minor in Statistics and Machine Learning. Following her doctoral studies, she conducted postdoctoral research in Fuels Modeling and Simulation at Idaho National Laboratory from August 2019 to December 2021. Professor Jin's research focuses on multiscale modeling of nuclear materials, investigating materials behavior in extreme environments, and studying defects and microstructure evolution in materials. She is also involved in the development of radiation-tolerant structural materials and the application of materials informatics. Her work aims to advance understanding and innovation in nuclear materials to improve their performance and safety under radiation exposure and other challenging conditions.

Research topics

• Materials science
• Chemistry
• Chemical physics
• Metallurgy
• Physics
• Composite material
• Thermodynamics
• Crystallography
• Condensed matter physics
• Nanotechnology
• Computational chemistry
• Nuclear magnetic resonance

Selected publications

• Swift Heavy-ion Induced Defects and Strain Evolution in GaN Epitaxial Heterostructures

  SSRN Electronic Journal · 2026-01-01

  preprintOpen access
  PublisherDOI

• Thermal Transport in Defective Uranium Nitride: Effects of Point Defects, Anharmonicity, and Electronic Contributions

  arXiv (Cornell University) · 2026-05-18

  preprintOpen accessSenior author

  The impact of point defects on thermal transport in uranium nitride (UN) is investigated using a MLIP combined with Green-Kubo (GK) and normal mode analysis (NMA) methods over 300-1500 K. In pristine UN, temperature-dependent calculations of lattice thermal conductivity reveal that four-phonon scattering is essential yet sufficient to accurately capture high temperature anharmonic phonon transport, as evidenced by close agreement between GK and ShengBTE calculations including three- and four-phonon processes. In defective systems, all types of point defects significantly reduce thermal conductivity at low temperature. Mode-resolved analysis further shows that interstitial defects introduce new phonon states due to a stronger local strain effect. Notably, the uranium interstitial leads to strong defect-phonon scattering over broad phonon spectrum, while the other point defects produce more selective scattering, with even reduced phonon scattering for some acoustic modes. The optical contribution to thermal conductivity remains nearly constant in the presence of IU, but decreases with increasing temperature for pristine and the other defect types. The total thermal conductivity, incorporating electron-phonon coupling and an estimated electronic contribution, yields excellent agreement with experiment in the pristine system, with electronic contributions dominating thermal transport above 600 K. Moreover, with defect-electron contribution introduced through a semiclassical electron-defect scattering model, it is found that (i) the total conductivity degradation follows IU, VU, IN, and VN in descending order, and (ii) electron-phonon coupling becomes negligible in defective systems. These results provide a unified understanding of defect-dependent thermal transport in UN.

  PublisherDOI

• Chemical Short-Range Order Regulates Hydrogen Energetics and Hydrogen-Dislocation Interactions in CoNiV

  arXiv (Cornell University) · 2026-04-07

  preprintOpen accessSenior author

  Chemical short-range order (CSRO) has emerged as a critical structural feature in concentrated alloys, yet its coupling with hydrogen remains an active discussion. Here, we develop a machine-learning interatomic potential for the Co-Ni-V-H system and investigate how CSRO regulates hydrogen energetics and dislocation behavior in CoNiV, an alloy with reported strong resistance to hydrogen embrittlement. We identify strong V-centered ordering that suppresses V-V clustering and significantly reshapes the hydrogen solution landscape. Compared to a chemically random alloy, the ordered state exhibits higher average hydrogen solution energies and a reduced population of strongly binding sites, indicating lower bulk hydrogen uptake. At partial dislocations, hydrogen preferentially segregates to tensile core regions, acting as a shallow, reversible trap with a much weaker effect compared to chemical trapping states. These results demonstrate that local chemical order strongly regulates hydrogen-dislocation coupling and provide an atomistic understanding for tuning hydrogen-assisted deformation in concentrated CoNiV alloys.

  PublisherDOI

• Kinetic interplay between chemical short-range order and grain boundaries in NiCoCr alloys under irradiation

  Figshare · 2026-04-08

  articleOpen access

  Chemical short-range order (CSRO) and grain boundary (GB) engineering are routes to enhance radiation damage tolerance in alloys. Here, we reveal that CSRO and GB interact in a sink-strength-dependent manner under irradiation in NiCoCr. Near a weak sink (Σ3 GB), CSRO reduces defect cluster growth by slowing interstitial diffusion and enhancing vacancy-interstitial recombinations. In contrast, near strong sinks such as Σ5 GBs, CSRO and GB act competitively for interstitial accumulation but synergistically to suppress large stacking-fault tetrahedra growth via enhanced recombination. Such mechanistic duality underscores the need for coordinated control of CSRO stability and GB sink strength to enhance radiation damage tolerance. This study reveals that CSRO and GB interact in a sink-strength-dependent manner, underscoring the need for coordinated control of CSRO stability and GB sink strength to enhance radiation tolerance.

  PublisherDOI

• Evaluation of structural properties and defect energetics in Al <i>x</i> Ga1− <i>x</i> N alloys

  Journal of Applied Physics · 2026-02-18

  articleOpen accessSenior author

  AlxGa1−xN alloys are essential for high-performance optoelectronic and power devices; yet, the role of composition on defect energetics remains underexplored, largely due to the limitations of first-principles methods in modeling disordered alloys. To address this, we employ a machine learning interatomic potential (MLIP) to investigate the structural and defect-related physical properties in AlxGa1−xN. The MLIP is first validated by reproducing the equation of state, lattice constants, and elastic constants of the binary end points, GaN and AlN, as well as known defect formation and migration energies from density functional theory and empirical potentials. We then apply the MLIP to evaluate elastic constants of AlGaN alloys, which reveals a non-linear relation with an alloying effect. Our results reveal that nitrogen Frenkel pair formation energies and the migration barriers for nitrogen point defects are highly sensitive to the local chemical environment and the migration path. In contrast, Ga and Al vacancy migration energies remain relatively insensitive to alloy composition, whereas their interstitial migration energies exhibit stronger compositional dependence. These results provide quantitative insight into how alloying influences defect energetics in AlGaN, informing defect engineering strategies for improved material performance.

  PublisherDOI

• Thermal Transport in Defective Uranium Nitride: Effects of Point Defects, Anharmonicity, and Electronic Contributions

  ArXiv.org · 2026-05-18

  articleOpen accessSenior author

  The impact of point defects on thermal transport in uranium nitride (UN) is investigated using a MLIP combined with Green-Kubo (GK) and normal mode analysis (NMA) methods over 300-1500 K. In pristine UN, temperature-dependent calculations of lattice thermal conductivity reveal that four-phonon scattering is essential yet sufficient to accurately capture high temperature anharmonic phonon transport, as evidenced by close agreement between GK and ShengBTE calculations including three- and four-phonon processes. In defective systems, all types of point defects significantly reduce thermal conductivity at low temperature. Mode-resolved analysis further shows that interstitial defects introduce new phonon states due to a stronger local strain effect. Notably, the uranium interstitial leads to strong defect-phonon scattering over broad phonon spectrum, while the other point defects produce more selective scattering, with even reduced phonon scattering for some acoustic modes. The optical contribution to thermal conductivity remains nearly constant in the presence of IU, but decreases with increasing temperature for pristine and the other defect types. The total thermal conductivity, incorporating electron-phonon coupling and an estimated electronic contribution, yields excellent agreement with experiment in the pristine system, with electronic contributions dominating thermal transport above 600 K. Moreover, with defect-electron contribution introduced through a semiclassical electron-defect scattering model, it is found that (i) the total conductivity degradation follows IU, VU, IN, and VN in descending order, and (ii) electron-phonon coupling becomes negligible in defective systems. These results provide a unified understanding of defect-dependent thermal transport in UN.

  PublisherOA PDF

• Kinetic interplay between chemical short-range order and grain boundaries in NiCoCr alloys under irradiation

  Figshare · 2026-04-08

  articleOpen access

  Chemical short-range order (CSRO) and grain boundary (GB) engineering are routes to enhance radiation damage tolerance in alloys. Here, we reveal that CSRO and GB interact in a sink-strength-dependent manner under irradiation in NiCoCr. Near a weak sink (Σ3 GB), CSRO reduces defect cluster growth by slowing interstitial diffusion and enhancing vacancy-interstitial recombinations. In contrast, near strong sinks such as Σ5 GBs, CSRO and GB act competitively for interstitial accumulation but synergistically to suppress large stacking-fault tetrahedra growth via enhanced recombination. Such mechanistic duality underscores the need for coordinated control of CSRO stability and GB sink strength to enhance radiation damage tolerance. This study reveals that CSRO and GB interact in a sink-strength-dependent manner, underscoring the need for coordinated control of CSRO stability and GB sink strength to enhance radiation tolerance.

  PublisherDOI

• Kinetic interplay between chemical short-range order and grain boundaries in NiCoCr alloys under irradiation

  Materials Research Letters · 2026-04-07

  articleOpen access

  Chemical short-range order (CSRO) and grain boundary (GB) engineering are routes to enhance radiation damage tolerance in alloys. Here, we reveal that CSRO and GB interact in a sink-strength-dependent manner under irradiation in NiCoCr. Near a weak sink (Σ3 GB), CSRO reduces defect cluster growth by slowing interstitial diffusion and enhancing vacancy-interstitial recombinations. In contrast, near strong sinks such as Σ5 GBs, CSRO and GB act competitively for interstitial accumulation but synergistically to suppress large stacking-fault tetrahedra growth via enhanced recombination. Such mechanistic duality underscores the need for coordinated control of CSRO stability and GB sink strength to enhance radiation damage tolerance.

  PublisherDOI

• Excessive dislocation loop growth in Uranium Mononitride under high temperature proton irradiation

  Scripta Materialia · 2026-04-03

  articleOpen access

  We investigate dislocation loop evolution in uranium mononitride under 2 MeV proton-irradiation at doses of 0.1 and 1 dpa, and temperatures of 25 °C and 800 °C. Transmission electron microscopy reveals strong dependencies of loop density and size on irradiation conditions. At room temperature, small loops dominate, while at 800 °C, loop density decreases but loop size increases significantly, with perfect loops exceeding 150 nm. This behavior contrasts with other fuels and surrogates (e.g., uranium dioxide, thorium dioxide, cerium dioxide, and zirconium carbide), where loops remain smaller under similar conditions. Rate theory modeling attributes this to lower defect migration barriers and higher uranium interstitial mobility in uranium mononitride. Molecular dynamics simulations suggest rapid unfaulting and enhanced mobility of perfect loops promote coalescence, forming fewer but much larger loops. These findings offer new insights into the distinct kinetics of faulted and perfect loop evolution in uranium mononitride, with implications for its thermal transport properties.

  PublisherDOI

• Chemical Short-Range Order Regulates Hydrogen Energetics and Hydrogen-Dislocation Interactions in CoNiV

  arXiv (Cornell University) · 2026-04-07

  articleOpen accessSenior author

  Chemical short-range order (CSRO) has emerged as a critical structural feature in concentrated alloys, yet its coupling with hydrogen remains an active discussion. Here, we develop a machine-learning interatomic potential for the Co-Ni-V-H system and investigate how CSRO regulates hydrogen energetics and dislocation behavior in CoNiV, an alloy with reported strong resistance to hydrogen embrittlement. We identify strong V-centered ordering that suppresses V-V clustering and significantly reshapes the hydrogen solution landscape. Compared to a chemically random alloy, the ordered state exhibits higher average hydrogen solution energies and a reduced population of strongly binding sites, indicating lower bulk hydrogen uptake. At partial dislocations, hydrogen preferentially segregates to tensile core regions, acting as a shallow, reversible trap with a much weaker effect compared to chemical trapping states. These results demonstrate that local chemical order strongly regulates hydrogen-dislocation coupling and provide an atomistic understanding for tuning hydrogen-assisted deformation in concentrated CoNiV alloys.

  PublisherOA PDF

Frequent coauthors

• J. W. Morris

  University of California, Berkeley

  22 shared

• Michael P. Short

  16 shared

• David H. Hurley

  15 shared

• Marat Khafizov

  The Ohio State University

  14 shared

• Penghui Cao

  University of California, Irvine

  14 shared

• Zhanxin Song

  Qingdao Institute of Bioenergy and Bioprocess Technology

  12 shared

• D. C. Chrzan

  Lawrence Berkeley National Laboratory

  12 shared

• Andrew M. Minor

  University of California, Berkeley

  11 shared

Labs

• Computational Nuclear Materials GroupPI

Education

• Ph.D., Nuclear Engineering

  University of California, Berkeley

  2005

• M.S., Nuclear Engineering

  University of California, Berkeley

  2001

• B.S., Nuclear Engineering

  Tsinghua University

  1998

Awards & honors

• NSF CAREER (July 2024 - June 2029)
• TMS Early Career Faculty Fellow Award (March 2026)
• Penn State Nuclear Engineering Research Award (April 2025)