Huaiyu Wang

All Publications

• Coupled order parameters and photoinduced domain walls in the charge density wave of (TaSe₄)₂I NPJ QUANTUM MATERIALS Duncan, R. A., Orenstein, G., Kim, S., Huang, Y., Wang, H., Teitelbaum, S. W., Stanton, J., Hurley, M., Miller, A., Leonard, N., Hanlon, D., Reis, D. A., Osaka, T., Kubota, Y., Togashi, T., Qu, K., Shoemaker, D. P., Sato, T., Trigo, M. 2025; 10 (1)

  View details for DOI 10.1038/s41535-025-00762-7

  View details for Web of Science ID 001479433100001

• Hidden domain boundary dynamics toward crystalline perfection. Proceedings of the National Academy of Sciences of the United States of America Mangu, A., Stoica, V. A., Zheng, H., Yang, T., Zhang, M., Wang, H. H., Zu, R., Nguyen, Q. L., Song, S., Das, S., Meisenheimer, P., Donoway, E., Chollet, M., Sun, Y., Turner, J. J., Freeland, J. W., Wen, H., Martin, L. W., Chen, L. Q., Gopalan, V., Zhu, D., Cao, Y., Lindenberg, A. M. 2025; 122 (2): e2407772122

  Abstract

  A central paradigm of nonequilibrium physics concerns the dynamics of heterogeneity and disorder, impacting processes ranging from the behavior of glasses to the emergent functionality of active matter. Understanding these complex mesoscopic systems requires probing the microscopic trajectories associated with irreversible processes, the role of fluctuations and entropy growth, and the timescales on which nonequilibrium responses are ultimately maintained. Approaches that illuminate these processes in model systems may enable a more general understanding of other heterogeneous nonequilibrium phenomena, and potentially define ultimate speed and energy cost limits for information processing technologies. Here, we apply ultrafast single-shot X-ray photon correlation spectroscopy to resolve the nonequilibrium, heterogeneous, and irreversible mesoscale dynamics during a light-induced phase transition in a (PbTiO3)16/(SrTiO3)16 superlattice. Such ferroelectric superlattice systems are a useful platform to study phase transitions and topological dynamics due to their high degree of tunability. This provides an approach for capturing the nucleation of the light-induced phase, the formation of transient mesoscale defects at the boundaries of the nuclei, and the eventual annihilation of these defects, even in systems with complex polarization topologies. We identify a nonequilibrium correlation response spanning >10 orders of magnitude in timescales, with multistep behavior similar to the plateaus observed in supercooled liquids and glasses. We further show how the observed time-dependent long-time correlations can be understood in terms of stochastic and non-Markovian dynamics of domain walls, encoded in waiting-time distributions with power-law tails. This work defines possibilities for probing the nonequilibrium and correlated dynamics of disordered and heterogeneous media.

  View details for DOI 10.1073/pnas.2407772122

  View details for PubMedID 39773030

• Author Correction: Non-equilibrium pathways to emergent polar supertextures. Nature materials Stoica, V. A., Yang, T., Das, S., Cao, Y., Wang, H. H., Kubota, Y., Dai, C., Padma, H., Sato, Y., Mangu, A., Nguyen, Q. L., Zhang, Z., Talreja, D., Zajac, M. E., Walko, D. A., DiChiara, A. D., Owada, S., Miyanishi, K., Tamasaku, K., Sato, T., Glownia, J. M., Esposito, V., Nelson, S., Hoffmann, M. C., Schaller, R. D., Lindenberg, A. M., Martin, L. W., Ramesh, R., Matsuda, I., Zhu, D., Chen, L. Q., Wen, H., Gopalan, V., Freeland, J. W. 2024

  View details for DOI 10.1038/s41563-024-02044-2

  View details for PubMedID 39402217

• Non-equilibrium pathways to emergent polar supertextures. Nature materials Stoica, V. A., Yang, T., Das, S., Cao, Y., Wang, H. H., Kubota, Y., Dai, C., Padma, H., Sato, Y., Mangu, A., Nguyen, Q. L., Zhang, Z., Talreja, D., Zajac, M. E., Walko, D. A., DiChiara, A. D., Owada, S., Miyanishi, K., Tamasaku, K., Sato, T., Glownia, J. M., Esposito, V., Nelson, S., Hoffmann, M. C., Schaller, R. D., Lindenberg, A. M., Martin, L. W., Ramesh, R., Matsuda, I., Zhu, D., Chen, L. Q., Wen, H., Gopalan, V., Freeland, J. W. 2024

  Abstract

  Ultrafast stimuli can stabilize metastable states of matter inaccessible by equilibrium means. Establishing the spatiotemporal link between ultrafast excitation and metastability is crucial to understand these phenomena. Here we utilize single-shot optical pump-X-ray probe measurements to capture snapshots of the emergence of a persistent polar vortex supercrystal in a heterostructure that hosts a fine balance between built-in electrostatic and elastic frustrations by design. By perturbing this balance with photoinduced charges, an initially heterogeneous mixture of polar phase disorders within a few picoseconds, leading to a state composed of disordered ferroelectric and suppressed vortex orders. On the picosecond-nanosecond timescales, transient labyrinthine fluctuations develop, accompanied by the recovery of the vortex order. On longer timescales, these fluctuations are progressively quenched by dynamical strain modulations, which drive the collective emergence of a single vortex supercrystal phase. Our results, corroborated by dynamical phase-field modelling, reveal non-equilibrium pathways following the ultrafast excitation of designer systems to persistent metastability.

  View details for DOI 10.1038/s41563-024-01981-2

  View details for PubMedID 39317816

  View details for PubMedCentralID 8024274

• Strong electron-phonon coupling driven pseudogap modulation and density-wave fluctuations in a correlated polar metal. Nature communications Wang, H. H., Xiong, Y., Padma, H., Wang, Y., Wang, Z., Claes, R., Brunin, G., Min, L., Zu, R., Wetherington, M. T., Wang, Y., Mao, Z., Hautier, G., Chen, L., Dabo, I., Gopalan, V. 2023; 14 (1): 5769

  Abstract

  There is tremendous interest in employing collective excitations of thelattice, spin, charge, and orbitals to tune strongly correlated electronic phenomena. We report such an effect in a ruthenate, Ca3Ru2O7, where two phonons with strong electron-phonon coupling modulate the electronic pseudogap as well as mediate charge and spin density wave fluctuations. Combining temperature-dependent Raman spectroscopy with density functional theory reveals two phonons, B2P and B2M, that are strongly coupled to electrons and whose scattering intensities respectively dominate in the pseudogap versus the metallic phases. The B2P squeezes the octahedra along the out of plane c-axis, while the B2M elongates it, thus modulating the Ru 4d orbital splitting and the bandwidth of the in-plane electron hopping; Thus, B2P opens the pseudogap, while B2M closes it. Moreover, the B2 phonons mediate incoherent charge and spin density wave fluctuations, as evidenced by changes in the background electronic Raman scattering that exhibit unique symmetry signatures. The polar order breaks inversion symmetry, enabling infrared activity of these phonons, paving the way for coherent light-driven control of electronic transport.

  View details for DOI 10.1038/s41467-023-41460-x

  View details for PubMedID 37723139

• Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe4)2I Revealed via Weak Photoexcitation. Nano letters Zhang, Y., Murthy, C., Kafle, T. R., You, W., Shi, X., Min, L., Wang, H. H., Li, N., Gopalan, V., Mao, Z., Rossnagel, K., Yang, L., Kapteyn, H., Nandkishore, R., Murnane, M. 2023

  Abstract

  The origin of the pseudogap in many strongly correlated materials has been a longstanding puzzle. Here, we present experimental evidence that many-body interactions among small Holstein polarons, i.e., the formation of bipolarons, are primarily responsible for the pseudogap in (TaSe4)2I. After weak photoexcitation of the material, we observe the appearance of both dispersive (single-particle bare band) and flat bands (single-polaron sub-bands) in the gap by using time- and angle-resolved photoemission spectroscopy. Based on Monte Carlo simulations of the Holstein model, we propose that the melting of pseudogap and emergence of new bands originate from a bipolaron to single-polaron crossover. We also observe dramatically different relaxation times for the excited in-gap states in (TaSe4)2I (∼600 fs) compared with another 1D material Rb0.3MoO3 (∼60 fs), which provides a new method for distinguishing between pseudogaps induced by polaronic or Luttinger-liquid many-body interactions.

  View details for DOI 10.1021/acs.nanolett.3c01078

  View details for PubMedID 37682637

• High-Pressure, High-Temperature Synthesis and Characterization of Polar and Magnetic LuCrWO₆ INORGANIC CHEMISTRY Kim, S., Tan, X., Frank, C. E., Deng, Z., Wang, H., Collins, L., Lapidus, S. H., Jin, C., Gopalan, V., Kalinin, S., Walker, D., Greenblatt, M. 2020; 59 (6): 3579-3584

  Abstract

  A new polar and magnetic oxide, LuCrWO6, was synthesized under high pressure (6 GPa) and high temperature (1673 K). LuCrWO6 is isostructural with the previously reported polar YCrWO6 (SG: Pna21, no. 33). The ordering of CrO6 and WO6 octahedra in the edge-shared dimers induce the polar structure. The effective size of rare earth, Ln cation does not seem to affect the symmetry of LnCrWO6. Second harmonic generation measurements of LuCrWO6 confirmed the noncentrosymmetric character and strong piezoelectric domains are observed from piezoresponse force microscopy at room temperature. LuCrWO6 exhibits antiferromagnetic behavior, TN, of ∼18 K with a Weiss temperature of -30.7 K.

  View details for DOI 10.1021/acs.inorgchem.9b02900

  View details for Web of Science ID 000526414000029

  View details for PubMedID 32100540