I am currently a postdoctoral condensed matter experimentalist, material physicist, optical spectroscopist, and X-ray scatterer at Stanford University and SLAC National Lab. At Stanford, I work jointly with Harold Hwang and Wei-Sheng Lee on investigating the complex interplay between charge, spin, lattice, and orbital degrees of freedom in functional oxide quantum materials under extreme (strain) conditions. My expertise lies in the use of scattering, spectroscopy and imaging techniques to investigate materials, utilizing a range of photon sources from high-brightness X-rays generated at large synchrotron light sources, to lab laser source.

Professional Education

  • Doctor of Philosophy, Massachusetts Institute of Technology (2022)
  • Bachelor of Science, Peking University, Physics (2016)

Stanford Advisors

All Publications

  • Sudden Collapse of Magnetic Order in Oxygen-Deficient Nickelate Films PHYSICAL REVIEW LETTERS Li, J., Green, R. J., Zhang, Z., Sutarto, R., Sadowski, J. T., Zhu, Z., Zhang, G., Zhou, D., Sun, Y., He, F., Ramanathan, S., Comin, R. 2021; 126 (18): 187602


    Antiferromagnetic order is a common and robust ground state in the parent (undoped) phase of several strongly correlated electron systems. The progressive weakening of antiferromagnetic correlations upon doping paves the way for a variety of emergent many-electron phenomena including unconventional superconductivity, colossal magnetoresistance, and collective charge-spin-orbital ordering. In this study, we explored the use of oxygen stoichiometry as an alternative pathway to modify the coupled magnetic and electronic ground state in the family of rare earth nickelates (RENiO_{3-x}). Using a combination of x-ray spectroscopy and resonant soft x-ray magnetic scattering, we find that, while oxygen vacancies rapidly alter the electronic configuration within the Ni and O orbital manifolds, antiferromagnetic order is remarkably robust to substantial levels of carrier doping, only to suddenly collapse beyond 0.21 e^{-}/Ni without an accompanying structural transition. Our work demonstrates that ordered magnetism in RENiO_{3-x} is mostly insensitive to carrier doping up to significant levels unseen in other transition-metal oxides. The sudden collapse of ordered magnetism upon oxygen removal may provide a new mechanism for solid-state magnetoionic switching and new applications in antiferromagnetic spintronics.

    View details for DOI 10.1103/PhysRevLett.126.187602

    View details for Web of Science ID 000652838100012

    View details for PubMedID 34018782

  • Distinction between pristine and disorder-perturbed charge density waves in ZrTe3 NATURE COMMUNICATIONS Yue, L., Xue, S., Li, J., Hu, W., Barbour, A., Zheng, F., Wang, L., Feng, J., Wilkins, S. B., Mazzoli, C., Comin, R., Li, Y. 2020; 11 (1): 98


    Charge density waves (CDWs) in the cuprate high-temperature superconductors have evoked much interest, yet their typical short-range nature has raised questions regarding the role of disorder. Here we report a resonant X-ray diffraction study of ZrTe[Formula: see text], a model CDW system, with focus on the influence of disorder. Near the CDW transition temperature, we observe two independent signals that arise concomitantly, only to become clearly separated in momentum while developing very different correlation lengths in the well-ordered state that is reached at a distinctly lower temperature. Anomalously slow dynamics of mesoscopic charge domains are further found near the transition temperature, in spite of the expected strong thermal fluctuations. Our observations signify the presence of distinct experimental fingerprints of pristine and disorder-perturbed CDWs. We discuss the latter also in the context of Friedel oscillations, which we argue might promote CDW formation via a self-amplifying process.

    View details for DOI 10.1038/s41467-019-13813-y

    View details for Web of Science ID 000511967900002

    View details for PubMedID 31911603

    View details for PubMedCentralID PMC6946692

  • Scale-invariant magnetic textures in the strongly correlated oxide NdNiO3 NATURE COMMUNICATIONS Li, J., Pelliciari, J., Mazzoli, C., Catalano, S., Simmons, F., Sadowski, J. T., Levitan, A., Gibert, M., Carlson, E., Triscone, J., Wilkins, S., Comin, R. 2019; 10: 4568


    Strongly correlated quantum solids are characterized by an inherently granular electronic fabric, with spatial patterns that can span multiple length scales in proximity to a critical point. Here, we use a resonant magnetic X-ray scattering nanoprobe with sub-100 nm spatial resolution to directly visualize the texture of antiferromagnetic domains in NdNiO3. Surprisingly, our measurements reveal a highly textured magnetic fabric, which we show to be robust and nonvolatile even after thermal erasure across its ordering temperature. The scale-free distribution of antiferromagnetic domains and its non-integral dimensionality point to a hitherto-unobserved magnetic fractal geometry in this system. These scale-invariant textures directly reflect the continuous nature of the magnetic transition and the proximity of this system to a critical point. The present study not only exposes the near-critical behavior in rare earth nickelates but also underscores the potential for X-ray scattering nanoprobes to image the multiscale signatures of criticality near a critical point.

    View details for DOI 10.1038/s41467-019-12502-0

    View details for Web of Science ID 000490117800001

    View details for PubMedID 31615992

    View details for PubMedCentralID PMC6794273

  • Possible strain-induced enhancement of the superconducting onset transition temperature in infinite-layer nickelates COMMUNICATIONS PHYSICS Ren, X., Li, J., Chen, W., Gao, Q., Sanchez, J. J., Hales, J., Luo, H., Rodolakis, F., Mcchesney, J. L., Xiang, T., Hu, J., Comin, R., Wang, Y., Zhou, X., Zhu, Z. 2023; 6 (1)
  • Discovery of charge order in a cuprate Mott insulator. Proceedings of the National Academy of Sciences of the United States of America Kang, M., Zhang, C. C., Schierle, E., McCoy, S., Li, J., Sutarto, R., Suter, A., Prokscha, T., Salman, Z., Weschke, E., Cybart, S., Wei, J. Y., Comin, R. 2023; 120 (30): e2302099120


    Copper oxide superconductors universally exhibit multiple forms of electronically ordered phases that break the native translational symmetry of the CuO2 planes. In underdoped cuprates with correlated metallic ground states, charge/spin stripes and incommensurate charge density waves (CDWs) have been experimentally observed over the years, while early theoretical studies also predicted the emergence of a Coulomb-frustrated 'charge crystal' phase in the very lightly doped, insulating limit of CuO2 planes. Here, we search for signatures of CDW order in very lightly hole-doped cuprates from the 123 family RBa2Cu3O7 - δ (RBCO; R: Y or rare earth), by using resonant X-ray scattering, electron transport, and muon spin rotation measurements to resolve the electronic and magnetic ground states fully. Specifically, Pr is used to substitute Y at the R-site to systematically suppress the superconductivity and access the extremely low hole-doping regime of the cuprate phase diagram without changing the oxygen stoichiometry. X-ray scattering data taken on Pr-doped YBCO thin films reveal an in-plane CDW order that follows the same linear evolution of wave vector versus hole concentration as oxygen-underdoped YBCO but extends all the way to the insulating and magnetically ordered Mott limit. Combined with the recent observation of charge crystal phase on an insulating surface of Bi2Sr2CaCu2O8 + z, our results in RBCO suggest that this electronic symmetry breaking is universally present in very lightly doped CuO2 planes. These findings bridge the gap between the Mott insulating state and the underdoped metallic state and underscore the prominent role that Coulomb-frustrated electronic phase separation plays among all cuprates.

    View details for DOI 10.1073/pnas.2302099120

    View details for PubMedID 37459539

  • Extreme ultraviolet transient gratings: A tool for nanoscale photoacoustics PHOTOACOUSTICS Foglia, L., Mincigrucci, R., Maznev, A. A., Baldi, G., Capotondi, F., Caporaletti, F., Comin, R., De Angelis, D., Duncan, R. A., Fainozzi, D., Kurdi, G., Li, J., Martinelli, A., Masciovecchio, C., Monaco, G., Milloch, A., Nelson, K. A., Occhialini, C. A., Pancaldi, M., Pedersoli, E., Pelli-Cresi, J. S., Simoncig, A., Travasso, F., Wehinger, B., Zanatta, M., Bencivenga, F. 2023; 29: 100453


    Collective lattice dynamics determine essential aspects of condensed matter, such as elastic and thermal properties. These exhibit strong dependence on the length-scale, reflecting the marked wavevector dependence of lattice excitations. The extreme ultraviolet transient grating (EUV TG) approach has demonstrated the potential of accessing a wavevector range corresponding to the 10s of nm length-scale, representing a spatial scale of the highest relevance for fundamental physics and forefront technology, previously inaccessible by optical TG and other inelastic scattering methods. In this manuscript we report on the capabilities of this technique in the context of probing thermoelastic properties of matter, both in the bulk and at the surface, as well as discussing future developments and practical considerations.

    View details for DOI 10.1016/j.pacs.2023.100453

    View details for Web of Science ID 000925925600001

    View details for PubMedID 36718271

    View details for PubMedCentralID PMC9883289

  • Ultrafast signatures of spin and orbital order in antiferromagnetic alpha-Sr2CrO4 COMMUNICATIONS PHYSICS Lee, M., Occhialini, C., Li, J., Zhu, Z., Sirica, N. S., Mix, L. T., Kim, S., Yarotski, D. A., Comin, R., Prasankumar, R. P. 2022; 5 (1)
  • Carrier Doping Physics of Rare Earth Perovskite Nickelates RENiO3 FRONTIERS IN PHYSICS Li, J., Ramanathan, S., Comin, R. 2022; 10
  • First-principles calculation of oxygen vacancy effects on the magnetic properties of the perovskite SrNiO3 PHYSICAL REVIEW MATERIALS Cho, E., Klyukin, K., Ning, S., Li, J., Comin, R., Green, R. J., Yildiz, B., Ross, C. A. 2021; 5 (9)
  • Doping-dependent phonon anomaly and charge-order phenomena in the HgBa2CuO4+delta and HgBa2CaCu2O6+delta superconductors PHYSICAL REVIEW B Wang, L., Yu, B., Jing, R., Luo, X., Zeng, J., Li, J., Bialo, I., Bluschke, M., Tang, Y., Freyermuth, J., Yu, G., Sutarto, R., He, F., Weschke, E., Tabis, W., Greven, M., Li, Y. 2020; 101 (22)
  • Temperature-independent thermal radiation PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Shahsafi, A., Roney, P., Zhou, Y., Zhang, Z., Xiao, Y., Wan, C., Wambold, R., Salman, J., Yu, Z., Li, J., Sadowski, J. T., Comin, R., Ramanathan, S., Kats, M. A. 2019; 116 (52): 26402-26406


    Thermal emission is the process by which all objects at nonzero temperatures emit light and is well described by the Planck, Kirchhoff, and Stefan-Boltzmann laws. For most solids, the thermally emitted power increases monotonically with temperature in a one-to-one relationship that enables applications such as infrared imaging and noncontact thermometry. Here, we demonstrated ultrathin thermal emitters that violate this one-to-one relationship via the use of samarium nickel oxide (SmNiO3), a strongly correlated quantum material that undergoes a fully reversible, temperature-driven solid-state phase transition. The smooth and hysteresis-free nature of this unique insulator-to-metal phase transition enabled us to engineer the temperature dependence of emissivity to precisely cancel out the intrinsic blackbody profile described by the Stefan-Boltzmann law, for both heating and cooling. Our design results in temperature-independent thermally emitted power within the long-wave atmospheric transparency window (wavelengths of 8 to 14 µm), across a broad temperature range of ∼30 °C, centered around ∼120 °C. The ability to decouple temperature and thermal emission opens a gateway for controlling the visibility of objects to infrared cameras and, more broadly, opportunities for quantum materials in controlling heat transfer.

    View details for DOI 10.1073/pnas.1911244116

    View details for Web of Science ID 000504656900041

    View details for PubMedID 31848248

    View details for PubMedCentralID PMC6936496

  • Carrier localization in perovskite nickelates from oxygen vacancies PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Kotiuga, M., Zhang, Z., Li, J., Rodolakis, F., Zhou, H., Sutarto, R., He, F., Wang, Q., Sun, Y., Wang, Y., Aghamiri, N., Hancock, S., Rokhinson, L. P., Landau, D. P., Abate, Y., Freeland, J. W., Comin, R., Ramanathan, S., Rabe, K. M. 2019; 116 (44): 21992-21997


    Point defects, such as oxygen vacancies, control the physical properties of complex oxides, relevant in active areas of research from superconductivity to resistive memory to catalysis. In most oxide semiconductors, electrons that are associated with oxygen vacancies occupy the conduction band, leading to an increase in the electrical conductivity. Here we demonstrate, in contrast, that in the correlated-electron perovskite rare-earth nickelates, RNiO3 (R is a rare-earth element such as Sm or Nd), electrons associated with oxygen vacancies strongly localize, leading to a dramatic decrease in the electrical conductivity by several orders of magnitude. This unusual behavior is found to stem from the combination of crystal field splitting and filling-controlled Mott-Hubbard electron-electron correlations in the Ni 3d orbitals. Furthermore, we show the distribution of oxygen vacancies in NdNiO3 can be controlled via an electric field, leading to analog resistance switching behavior. This study demonstrates the potential of nickelates as testbeds to better understand emergent physics in oxide heterostructures as well as candidate systems in the emerging fields of artificial intelligence.

    View details for DOI 10.1073/pnas.1910490116

    View details for Web of Science ID 000493720200013

    View details for PubMedID 31611403

    View details for PubMedCentralID PMC6825322

  • Putting the gap on the map NATURE PHYSICS Li, J., Comin, R. 2019; 15 (8): 736-738
  • Resolving the nature of electronic excitations in resonant inelastic x-ray scattering PHYSICAL REVIEW B Kang, M., Pelliciari, J., Krockenberger, Y., Li, J., McNally, D. E., Paris, E., Liang, R., Hardy, W. N., Bonn, D. A., Yamamoto, H., Schmitt, T., Comin, R. 2019; 99 (4)
  • Growth and characterization of HgBa2CaCu2O6 +/-delta and HgBa2Ca2Cu3O8 +/-delta crystals PHYSICAL REVIEW MATERIALS Wang, L., Luo, X., Li, J., Zeng, J., Cheng, M., Freyermuth, J., Tang, Y., Yu, B., Yu, G., Greven, M., Li, Y. 2018; 2 (12)
  • Perovskite nickelates as electric-field sensors in salt water NATURE Zhang, Z., Schwanz, D., Narayanan, B., Kotiuga, M., Dura, J. A., Cherukara, M., Zhou, H., Freeland, J. W., Li, J., Sutarto, R., He, F., Wu, C., Zhu, J., Sun, Y., Ramadoss, K., Nonnenmann, S. S., Yu, N., Comin, R., Rabe, K. M., Sankaranarayanan, S. S., Ramanathan, S. 2018; 553 (7686): 68-+


    Designing materials to function in harsh environments, such as conductive aqueous media, is a problem of broad interest to a range of technologies, including energy, ocean monitoring and biological applications. The main challenge is to retain the stability and morphology of the material as it interacts dynamically with the surrounding environment. Materials that respond to mild stimuli through collective phase transitions and amplify signals could open up new avenues for sensing. Here we present the discovery of an electric-field-driven, water-mediated reversible phase change in a perovskite-structured nickelate, SmNiO3. This prototypical strongly correlated quantum material is stable in salt water, does not corrode, and allows exchange of protons with the surrounding water at ambient temperature, with the concurrent modification in electrical resistance and optical properties being capable of multi-modal readout. Besides operating both as thermistors and pH sensors, devices made of this material can detect sub-volt electric potentials in salt water. We postulate that such devices could be used in oceanic environments for monitoring electrical signals from various maritime vessels and sea creatures.

    View details for DOI 10.1038/nature25008

    View details for Web of Science ID 000419769300031

    View details for PubMedID 29258293

  • Habituation based synaptic plasticity and organismic learning in a quantum perovskite NATURE COMMUNICATIONS Zuo, F., Panda, P., Kotiuga, M., Li, J., Kang, M., Mazzoli, C., Zhou, H., Barbour, A., Wilkins, S., Narayanan, B., Cherukara, M., Zhang, Z., Sankaranarayanan, S. S., Comin, R., Rabe, K. M., Roy, K., Ramanathan, S. 2017; 8: 240


    A central characteristic of living beings is the ability to learn from and respond to their environment leading to habit formation and decision making. This behavior, known as habituation, is universal among all forms of life with a central nervous system, and is also observed in single-cell organisms that do not possess a brain. Here, we report the discovery of habituation-based plasticity utilizing a perovskite quantum system by dynamical modulation of electron localization. Microscopic mechanisms and pathways that enable this organismic collective charge-lattice interaction are elucidated by first-principles theory, synchrotron investigations, ab initio molecular dynamics simulations, and in situ environmental breathing studies. We implement a learning algorithm inspired by the conductance relaxation behavior of perovskites that naturally incorporates habituation, and demonstrate learning to forget: a key feature of animal and human brains. Incorporating this elementary skill in learning boosts the capability of neural computing in a sequential, dynamic environment.Habituation is a learning mechanism that enables control over forgetting and learning. Zuo, Panda et al., demonstrate adaptive synaptic plasticity in SmNiO3 perovskites to address catastrophic forgetting in a dynamic learning environment via hydrogen-induced electron localization.

    View details for DOI 10.1038/s41467-017-00248-6

    View details for Web of Science ID 000407552400001

    View details for PubMedID 28808316

    View details for PubMedCentralID PMC5556077

  • Prominent Role of Spin-Orbit Coupling in FeSe Revealed by Inelastic Neutron Scattering PHYSICAL REVIEW X Ma, M., Bourges, P., Sidis, Y., Xu, Y., Li, S., Hu, B., Li, J., Wang, F., Li, Y. 2017; 7 (2)
  • Nematic Crossover in BaFe2As2 under Uniaxial Stress PHYSICAL REVIEW LETTERS Ren, X., Duan, L., Hu, Y., Li, J., Zhang, R., Luo, H., Dai, P., Li, Y. 2015; 115 (19): 197002


    Raman scattering can detect spontaneous point-group symmetry breaking without resorting to single-domain samples. Here, we use this technique to study BaFe(2)As(2), the parent compound of the "122" Fe-based superconductors. We show that an applied compression along the Fe-Fe direction, which is commonly used to produce untwinned orthorhombic samples, changes the structural phase transition at temperature T(s) into a crossover that spans a considerable temperature range above T(s). Even in crystals that are not subject to any applied force, a distribution of substantial residual stress remains, which may explain phenomena that are seemingly indicative of symmetry breaking above T(s). Our results are consistent with an onset of spontaneous nematicity only below T(s).

    View details for DOI 10.1103/PhysRevLett.115.197002

    View details for Web of Science ID 000364216600006

    View details for PubMedID 26588407