Ziyan Zhu

All Publications

• Multi-moiré trilayer graphene: Lattice relaxation, electronic structure, and magic angles PHYSICAL REVIEW B Yang, C., May-Mann, J., Zhu, Z., Devakul, T. 2024; 110 (11)

  View details for DOI 10.1103/PhysRevB.110.115434

  View details for Web of Science ID 001327393800002

• Opto-twistronic Hall effect in a three-dimensional spiral lattice. Nature Ji, Z., Zhao, Y., Chen, Y., Zhu, Z., Wang, Y., Liu, W., Modi, G., Mele, E. J., Jin, S., Agarwal, R. 2024

  Abstract

  Studies of moiré systems have explained the effect of superlattice modulations on their properties, demonstrating new correlated phases1. However, most experimental studies have focused on a few layers in two-dimensional systems. Extending twistronics to three dimensions, in which the twist extends into the third dimension, remains underexplored because of the challenges associated with the manual stacking of layers. Here we study three-dimensional twistronics using a self-assembled twisted spiral superlattice of multilayered WS2. Our findings show an opto-twistronic Hall effect driven by structural chirality and coherence length, modulated by the moiré potential of the spiral superlattice. This is an experimental manifestation of the noncommutative geometry of the system. We observe enhanced light-matter interactions and an altered dependence of the Hall coefficient on photon momentum. Our model suggests contributions from higher-order quantum geometric quantities to this observation, providing opportunities for designing quantum-materials-based optoelectronic lattices with large nonlinearities.

  View details for DOI 10.1038/s41586-024-07949-1

  View details for PubMedID 39294380

  View details for PubMedCentralID 10439888

• Tunable inter-moiré physics in consecutively twisted trilayer graphene PHYSICAL REVIEW B Ren, W., Davydov, K., Zhu, Z., Ma, J., Watanabe, K., Taniguchi, T., Kaxiras, E., Luskin, M., Wang, K. 2024; 110 (11)

  View details for DOI 10.1103/PhysRevB.110.115404

  View details for Web of Science ID 001310147700001

• Twisto-Electrochemical Activity Volcanoes in Trilayer Graphene. Journal of the American Chemical Society Babar, M., Zhu, Z., Kurchin, R., Kaxiras, E., Viswanathan, V. 2024; 146 (23): 16105-16111

  Abstract

  In this work, we develop a twist-dependent electrochemical activity map, combining a low-energy continuum electronic structure model with modified Marcus-Hush-Chidsey kinetics in trilayer graphene. We identify a counterintuitive rate enhancement region spanning the magic angle curve and incommensurate twists in the system geometry. We find a broad activity peak with a ruthenium hexamine redox couple in regions corresponding to both magic angles and incommensurate angles, a result qualitatively distinct from the twisted bilayer case. Flat bands and incommensurability offer new avenues for reaction rate enhancements in electrochemical transformations.

  View details for DOI 10.1021/jacs.4c03464

  View details for PubMedID 38829312

  View details for PubMedCentralID PMC11177310

• Local atomic stacking and symmetry in twisted graphene trilayers. Nature materials Craig, I. M., Van Winkle, M., Groschner, C., Zhang, K., Dowlatshahi, N., Zhu, Z., Taniguchi, T., Watanabe, K., Griffin, S. M., Bediako, D. K. 2024; 23 (3): 323-330

  Abstract

  Moiré superlattices formed by twisting trilayers of graphene are a useful model for studying correlated electron behaviour and offer several advantages over their formative bilayer analogues, including a more diverse collection of correlated phases and more robust superconductivity. Spontaneous structural relaxation alters the behaviour of moiré superlattices considerably and has been suggested to play an important role in the relative stability of superconductivity in trilayers. Here we use an interferometric four-dimensional scanning transmission electron microscopy approach to directly probe the local graphene layer alignment over a wide range of trilayer graphene structures. Our results inform a thorough understanding of how reconstruction modulates the local lattice symmetries crucial for establishing correlated phases in twisted graphene trilayers, evincing a relaxed structure that is markedly different from that proposed previously.

  View details for DOI 10.1038/s41563-023-01783-y

  View details for PubMedID 38191631

  View details for PubMedCentralID 10209090

• HubbardNet: Efficient predictions of the Bose-Hubbard model spectrum with deep neural networks PHYSICAL REVIEW RESEARCH Zhu, Z., Mattheakis, M., Pan, W., Kaxiras, E. 2023; 5 (4)

  View details for DOI 10.1103/PhysRevResearch.5.043084

  View details for Web of Science ID 001098159100004

• Topology of rotating stratified fluids with and without background shear flow PHYSICAL REVIEW RESEARCH Zhu, Z., Li, C., Marston, J. B. 2023; 5 (3)

  View details for DOI 10.1103/PhysRevResearch.5.033191

  View details for Web of Science ID 001135530100002

• Pressure-enhanced fractional Chern insulators along a magic line in moire transition metal dichalcogenides PHYSICAL REVIEW RESEARCH Morales-Duran, N., Wang, J., Schleder, G. R., Angeli, M., Zhu, Z., Kaxiras, E., Repellin, C., Cano, J. 2023; 5 (3)

  View details for DOI 10.1103/PhysRevResearch.5.L032022

  View details for Web of Science ID 001052961500004

• Anomalous Interfacial Electron-Transfer Kinetics in Twisted Trilayer Graphene Caused by Layer-Specific Localization. ACS central science Zhang, K., Yu, Y., Carr, S., Babar, M., Zhu, Z., Kim, B. J., Groschner, C., Khaloo, N., Taniguchi, T., Watanabe, K., Viswanathan, V., Bediako, D. K. 2023; 9 (6): 1119-1128

  Abstract

  Interfacial electron-transfer (ET) reactions underpin the interconversion of electrical and chemical energy. It is known that the electronic state of electrodes strongly influences ET rates because of differences in the electronic density of states (DOS) across metals, semimetals, and semiconductors. Here, by controlling interlayer twists in well-defined trilayer graphene moirés, we show that ET rates are strikingly dependent on electronic localization in each atomic layer and not the overall DOS. The large degree of tunability inherent to moiré electrodes leads to local ET kinetics that range over 3 orders of magnitude across different constructions of only three atomic layers, even exceeding rates at bulk metals. Our results demonstrate that beyond the ensemble DOS, electronic localization is critical in facilitating interfacial ET, with implications for understanding the origin of high interfacial reactivity typically exhibited by defects at electrode-electrolyte interfaces.

  View details for DOI 10.1021/acscentsci.3c00326

  View details for PubMedID 37396866

  View details for PubMedCentralID PMC10311658

• Domain-Dependent Surface Adhesion in Twisted Few-Layer Graphene: Platform for Moire-Assisted Chemistry. Nano letters Hsieh, V., Halbertal, D., Finney, N. R., Zhu, Z., Gerber, E., Pizzochero, M., Kucukbenli, E., Schleder, G. R., Angeli, M., Watanabe, K., Taniguchi, T., Kim, E., Kaxiras, E., Hone, J., Dean, C. R., Basov, D. N. 2023

  Abstract

  Twisted van der Waals multilayers are widely regarded as a rich platform to access novel electronic phases thanks to the multiple degrees of freedom available for controlling their electronic and chemical properties. Here, we propose that the stacking domains that form naturally due to the relative twist between successive layers act as an additional "knob" for controlling the behavior of these systems and report the emergence and engineering of stacking domain-dependent surface chemistry in twisted few-layer graphene. Using mid-infrared near-field optical microscopy and atomic force microscopy, we observe a selective adhesion of metallic nanoparticles and liquid water at the domains with rhombohedral stacking configurations of minimally twisted double bi- and trilayer graphene. Furthermore, we demonstrate that the manipulation of nanoparticles located at certain stacking domains can locally reconfigure the moire superlattice in their vicinity at the micrometer scale. Our findings establish a new approach to controlling moire-assisted chemistry and nanoengineering.

  View details for DOI 10.1021/acs.nanolett.2c04137

  View details for PubMedID 37036942

• Electric field tunable layer polarization in graphene/boron-nitride twisted quadrilayer superlattices PHYSICAL REVIEW B Zhu, Z., Carr, S., Ma, Q., Kaxiras, E. 2022; 106 (20)

  View details for DOI 10.1103/PhysRevB.106.205134

  View details for Web of Science ID 000893198000002

• Gate-tunable Veselago interference in a bipolar graphene microcavity. Nature communications Zhang, X., Ren, W., Bell, E., Zhu, Z., Tsai, K., Luo, Y., Watanabe, K., Taniguchi, T., Kaxiras, E., Luskin, M., Wang, K. 2022; 13 (1): 6711

  Abstract

  The relativistic charge carriers in monolayer graphene can be manipulated in manners akin to conventional optics. Klein tunneling and Veselago lensing have been previously demonstrated in ballistic graphene pn-junction devices, but collimation and focusing efficiency remains relatively low, preventing realization of advanced quantum devices and controlled quantum interference. Here, we present a graphene microcavity defined by carefully-engineered local strain and electrostatic fields. Electrons are manipulated to form an interference path inside the cavity at zero magnetic field via consecutive Veselago refractions. The observation of unique Veselago interference peaks via transport measurement and their magnetic field dependence agrees with the theoretical expectation. We further utilize Veselago interference to demonstrate localization of uncollimated electrons and thus improvement in collimation efficiency. Our work sheds new light on relativistic single-particle physics and provide a new device concept toward next-generation quantum devices based on manipulation of ballistic electron trajectory.

  View details for DOI 10.1038/s41467-022-34347-w

  View details for PubMedID 36344499

• Low-energy moire phonons in twisted bilayer van der Waals heterostructures PHYSICAL REVIEW B Lu, J. Z., Zhu, Z., Angeli, M., Larson, D. T., Kaxiras, E. 2022; 106 (14)

  View details for DOI 10.1103/PhysRevB.106.144305

  View details for Web of Science ID 000870987800003

• Correlated Insulating States and Transport Signature of Superconductivity in Twisted Trilayer Graphene Superlattices. Physical review letters Zhang, X., Tsai, K. T., Zhu, Z., Ren, W., Luo, Y., Carr, S., Luskin, M., Kaxiras, E., Wang, K. 2021; 127 (16): 166802

  Abstract

  Layers of two-dimensional materials stacked with a small twist angle give rise to beating periodic patterns on a scale much larger than the original lattice, referred to as a "moiré superlattice." Here, we demonstrate a higher-order "moiré of moiré" superlattice in twisted trilayer graphene with two consecutive small twist angles. We report correlated insulating states near the half filling of the moiré of moiré superlattice at an extremely low carrier density (∼10^{10}  cm^{-2}), near which we also report a zero-resistance transport behavior typically expected in a 2D superconductor. The full-occupancy (ν=-4 and ν=4) states are semimetallic and gapless, distinct from the twisted bilayer systems.

  View details for DOI 10.1103/PhysRevLett.127.166802

  View details for PubMedID 34723600

• Spectroscopic Signatures of Interlayer Coupling in Janus MoSSe/MoS2 Heterostructures. ACS nano Zhang, K., Guo, Y., Larson, D. T., Zhu, Z., Fang, S., Kaxiras, E., Kong, J., Huang, S. 2021; 15 (9): 14394-14403

  Abstract

  The interlayer coupling in van der Waals heterostructures governs a variety of optical and electronic properties. The intrinsic dipole moment of Janus transition metal dichalcogenides (TMDs) offers a simple and versatile approach to tune the interlayer interactions. In this work, we demonstrate how the van der Waals interlayer coupling and charge transfer of Janus MoSSe/MoS2 heterobilayers can be tuned by the twist angle and interface composition. Specifically, the Janus heterostructures with a sulfur/sulfur (S/S) interface display stronger interlayer coupling than the heterostructures with a selenium/sulfur (Se/S) interface as shown by the low-frequency Raman modes. The differences in interlayer interactions are explained by the interlayer distance computed by density-functional theory (DFT). More intriguingly, the built-in electric field contributed by the charge density redistribution and interlayer coupling also play important roles in the interfacial charge transfer. Namely, the S/S and Se/S interfaces exhibit different levels of photoluminescence (PL) quenching of MoS2 A exciton, suggesting enhanced and reduced charge transfer at the S/S and Se/S interface, respectively. Our work demonstrates how the asymmetry of Janus TMDs can be used to tailor the interfacial interactions in van der Waals heterostructures.

  View details for DOI 10.1021/acsnano.1c03779

  View details for PubMedID 34463476

• Twisted Trilayer Graphene: A Precisely Tunable Platform for Correlated Electrons. Physical review letters Zhu, Z., Carr, S., Massatt, D., Luskin, M., Kaxiras, E. 2020; 125 (11): 116404

  Abstract

  We introduce twisted trilayer graphene (tTLG) with two independent twist angles as an ideal system for the precise tuning of the electronic interlayer coupling to maximize the effect of correlated behaviors. As established by experiment and theory in the related twisted bilayer graphene system, van Hove singularities (VHS) in the density of states can be used as a proxy of the tendency for correlated behaviors. To explore the evolution of VHS in the twist-angle phase space of tTLG, we present a general low-energy electronic structure model for any pair of twist angles. We show that the basis of the model has infinite dimensions even at a finite energy cutoff and that no Brillouin zone exists even in the continuum limit. Using this model, we demonstrate that the tTLG system exhibits a wide range of magic angles at which VHS merge and that the density of states has a sharp peak at the charge-neutrality point through two distinct mechanisms: the incommensurate perturbation of twisted bilayer graphene's flatbands or the equal hybridization between two bilayer moiré superlattices.

  View details for DOI 10.1103/PhysRevLett.125.116404

  View details for PubMedID 32975975

• Electronic structure calculations of twisted multi-layer graphene superlattices 2D MATERIALS Tritsaris, G. A., Carr, S., Zhu, Z., Xie, Y., Torrisi, S. B., Tang, J., Mattheakis, M., Larson, D. T., Kaxiras, E. 2020; 7 (3)

  View details for DOI 10.1088/2053-1583/ab8f62

  View details for Web of Science ID 000545021300001

• Modeling mechanical relaxation in incommensurate trilayer van der Waals heterostructures PHYSICAL REVIEW B Zhu, Z., Cazeaux, P., Luskin, M., Kaxiras, E. 2020; 101 (22)

  View details for DOI 10.1103/PhysRevB.101.224107

  View details for Web of Science ID 000538714300004

• Topological Gaseous Plasmon Polariton in Realistic Plasma. Physical review letters Parker, J. B., Marston, J. B., Tobias, S. M., Zhu, Z. 2020; 124 (19): 195001

  Abstract

  Nontrivial topology in bulk matter has been linked with the existence of topologically protected interfacial states. We show that a gaseous plasmon polariton (GPP), an electromagnetic surface wave existing at the boundary of magnetized plasma and vacuum, has a topological origin that arises from the nontrivial topology of magnetized plasma. Because a gaseous plasma cannot sustain a sharp interface with discontinuous density, one must consider a gradual density falloff with scale length comparable to or longer than the wavelength of the wave. We show that the GPP may be found within a gapped spectrum in present-day laboratory devices, suggesting that platforms are currently available for experimental investigation of topological wave physics in plasmas.

  View details for DOI 10.1103/PhysRevLett.124.195001

  View details for PubMedID 32469547

• Ultraheavy and Ultrarelativistic Dirac Quasiparticles in Sandwiched Graphenes. Nano letters Carr, S., Li, C., Zhu, Z., Kaxiras, E., Sachdev, S., Kruchkov, A. 2020; 20 (5): 3030-3038

  Abstract

  Electrons in quantum materials exhibiting coexistence of dispersionless (flat) bands piercing dispersive (steep) bands give rise to strongly correlated phenomena and are associated with unconventional superconductivity. We show that in twisted sandwiched graphene (TSWG)-a three-layer van der Waals heterostructure with a twisted middle layer-steep Dirac cones can coexist with dramatic band flattening at the same energy scale, if twisted by 1.5°. This phenomenon is not stable in the simplified continuum models. The key result of this Letter is that the flat bands become stable only as a consequence of lattice relaxation processes included in our atomistic calculations. Further on, external fields can change the relative energy offset between the Dirac cone vertex and the flat bands and enhance band hybridization, which could permit controlling correlated phases. Our work establishes twisted sandwiched graphene as a new platform for research into strongly interacting two-dimensional quantum matter.

  View details for DOI 10.1021/acs.nanolett.9b04979

  View details for PubMedID 32208724

• Exact continuum model for low-energy electronic states of twisted bilayer graphene PHYSICAL REVIEW RESEARCH Carr, S., Fang, S., Zhu, Z., Kaxiras, E. 2019; 1 (1)

  View details for DOI 10.1103/PhysRevResearch.1.013001

  View details for Web of Science ID 000600559800009

• First M87 Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole ASTROPHYSICAL JOURNAL LETTERS Akiyama, K., Alberdi, A., Alef, W., Asada, K., Azulay, R., Baczko, A., Ball, D., Balokovic, M., Barrett, J., Bintley, D., Blackburn, L., Boland, W., Bouman, K. L., Bower, G. C., Bremer, M., Brinkerink, C. D., Brissenden, R., Britzen, S., Broderick, A. E., Broguiere, D., Bronzwaer, T., Byun, D., Carlstrom, J. E., Chael, A., Chan, C., Chatterjee, S., Chatterjee, K., Chen, M., Chen, Y., Cho, I., Christian, P., Conway, J. E., Cordes, J. M., Crew, G. B., Cui, Y., Davelaar, J., De Laurentis, M., Deane, R., Dempsey, J., Desvignes, G., Dexter, J., Doeleman, S. S., Eatough, R. P., Falcke, H., Fish, V. L., Fomalont, E., Fraga-Encinas, R., Freeman, W. T., Friberg, P., Fromm, C. M., Gomez, J. L., Galison, P., Gammie, C. F., Garcia, R., Gentaz, O., Georgiev, B., Goddi, C., Gold, R., Gu, M., Gurwell, M., Hada, K., Hecht, M. H., Hesper, R., Ho, L. C., Ho, P., Honma, M., Huang, C. L., Huang, L., Hughes, D. H., Ikeda, S., Inoue, M., Issaoun, S., James, D. J., Jannuzi, B. T., Janssen, M., Jeter, B., Jiang, W., Johnson, M. D., Jorstad, S., Jung, T., Karami, M., Karuppusamy, R., Kawashima, T., Keating, G. K., Kettenis, M., Kim, J., Kim, J., Kim, J., Kino, M., Koay, J., Koch, P. M., Koyama, S., Kramer, M., Kramer, C., Krichbaum, T. P., Kuo, C., Lauer, T. R., Lee, S., Li, Y., Li, Z., Lindqvist, M., Liu, K., Liuzzo, E., Lo, W., Lobanov, A. P., Loinard, L., Lonsdale, C., Lu, R., MacDonald, N. R., Mao, J., Markoff, S., Marrone, D. P., Marscher, A. P., Marti-Vidal, I., Matsushita, S., Matthews, L. D., Medeiros, L., Menten, K. M., Mizuno, Y., Mizuno, I., Moran, J. M., Moriyama, K., Moscibrodzka, M., Mueller, C., Nagai, H., Nagar, N. M., Nakamura, M., Narayan, R., Narayanan, G., Natarajan, I., Neri, R., Ni, C., Noutsos, A., Okino, H., Olivares, H., Ortiz-Leon, G. N., Oyama, T., Ozel, F., Palumbo, D. M., Patel, N., Pen, U., Pesce, D. W., Pietu, V., Plambeck, R., PopStefanija, A., Porth, O., Prather, B., Preciado-Lopez, J. A., Psaltis, D., Pu, H., Ramakrishnan, V., Rao, R., Rawlings, M. G., Raymond, A. W., Rezzolla, L., Ripperda, B., Roelofs, F., Rogers, A., Ros, E., Rose, M., Roshanineshat, A., Rottmann, H., Roy, A. L., Ruszczyk, C., Ryan, B. R., Rygl, K. J., Sanchez, S., Sanchez-Arguelles, D., Sasada, M., Savolainen, T., Schloerb, F., Schuster, K., Shao, L., Shen, Z., Small, D., Sohn, B., SooHoo, J., Tazaki, F., Tiede, P., Tilanus, R. J., Titus, M., Toma, K., Torne, P., Trent, T., Trippe, S., Tsuda, S., van Bemmel, I., van Langevelde, H., van Rossum, D. R., Wagner, J., Wardle, J., Weintroub, J., Wex, N., Wharton, R., Wielgus, M., Wong, G. N., Wu, Q., Young, K., Young, A., Younsi, Z., Yuan, F., Yuan, Y., Zensus, J., Zhao, G., Zhao, S., Zhu, Z., Algaba, J., Allardi, A., Amestica, R., Anczarski, J., Bach, U., Baganoff, F. K., Beaudoin, C., Benson, B. A., Berthold, R., Blanchard, J. M., Blundell, R., Bustamente, S., Cappallo, R., Castillo-Dominguez, E., Chang, C., Chang, S., Chang, S., Chen, C., Chilson, R., Chuter, T. C., Rosado, R., Coulson, I. M., Crawford, T. M., Crowley, J., David, J., Derome, M., Dexter, M., Dornbusch, S., Dudevoir, K. A., Dzib, S. A., Eckart, A., Eckert, C., Erickson, N. R., Everett, W. B., Faber, A., Farah, J. R., Fath, V., Folkers, T. W., Forbes, D. C., Freund, R., Gomez-Ruiz, A. I., Gale, D. M., Gao, F., Geertsema, G., Graham, D. A., Greer, C. H., Grosslein, R., Gueth, F., Haggard, D., Halverson, N. W., Han, C., Han, K., Hao, J., Hasegawa, Y., Henning, J. W., Hernandez-Gomez, A., Herrero-Illana, R., Heyminck, S., Hirota, A., Hoge, J., Huang, Y., Impellizzeri, C., Jiang, H., Kamble, A., Keisler, R., Kimura, K., Kono, Y., Kubo, D., Kuroda, J., Lacasse, R., Laing, R. A., Leitch, E. M., Li, C., Lin, L., Liu, C., Liu, K., Lu, L., Marson, R. G., Martin-Cocher, P. L., Massingill, K. D., Matulonis, C., McColl, M. P., McWhirter, S. R., Messias, H., Meyer-Zhao, Z., Michalik, D., Montana, A., Montgomerie, W., Mora-Klein, M., Muders, D., Nadolski, A., Navarro, S., Neilsen, J., Nguyen, C. H., Nishioka, H., Norton, T., Nowak, M. A., Nystrom, G., Ogawa, H., Oshiro, P., Oyama, T., Parsons, H., Paine, S. N., Penalver, J., Phillips, N. M., Poirier, M., Pradel, N., Primiani, R. A., Raffin, P. A., Rahlin, A. S., Reiland, G., Risacher, C., Ruiz, I., Saez-Madain, A. F., Sassella, R., Schellart, P., Shaw, P., Silva, K. M., Shiokawa, H., Smith, D. R., Snow, W., Souccar, K., Sousa, D., Sridharan, T. K., Srinivasan, R., Stahm, W., Stark, A. A., Story, K., Timmer, S. T., Vertatschitsch, L., Walther, C., Wei, T., Whitehorn, N., Whitney, A. R., Woody, D. P., Wouterloot, J. A., Wright, M., Yamaguchi, P., Yu, C., Zeballos, M., Zhang, S., Ziurys, L., Event Horizon Telescope Collaborat 2019; 875 (1)

  View details for DOI 10.3847/2041-8213/ab0ec7

  View details for Web of Science ID 000464210800001

• Testing General Relativity with the Black Hole Shadow Size and Asymmetry of Sagittarius A*: Limitations from Interstellar Scattering ASTROPHYSICAL JOURNAL Zhu, Z., Johnson, M. D., Narayan, R. 2019; 870 (1)

  View details for DOI 10.3847/1538-4357/aaef3d

  View details for Web of Science ID 000454541100006

• Chaotic edge density fluctuations in the Alcator C-Mod tokamak PHYSICS OF PLASMAS Zhu, Z., White, A. E., Carter, T. A., Baek, S. G., Terry, J. L. 2017; 24 (4)

  View details for DOI 10.1063/1.4978784

  View details for Web of Science ID 000400390700035