Ruishi Qi

Appointments

• Stanford Science Fellow Stanford University (2026-) — faculty host: Prof. Tony F. Heinz

Education

• Ph.D. in Physics University of California, Berkeley (2026) — advisor: Prof. Feng Wang
  Thesis: Correlated exciton physics in van der Waals electron-hole bilayers
• M.A. in Physics University of California, Berkeley (2022)
• B.S. in Physics Peking University (2020) — advisor: Prof. Peng Gao
  Undergraduate thesis: Probing phonon dispersion in individual BN nanotubes using STEM-EELS

Experience

• Postdoctoral Fellow Edward L. Ginzton Laboratory, Department of Applied Physics, Stanford University (host: Prof. Tony F. Heinz) (2026-)
• Graduate Student Researcher Ultrafast nano-optics group at UC Berkeley (PI: Prof. Feng Wang) (2021-2026)
• Graduate Student Instructor Department of Physics, UC Berkeley (2020-2021)
• Research Assistant Electron microscopy laboratory at Peking University (PI: Prof. Peng Gao) (2020-2021), undergraduate researcher (2018-2020)
• Exchange Visitor Coherent imaging group, Department of Physics and Astronomy, UCLA (PI: Prof. Jianwei Miao) (2019)

Awards and Honors

• Stanford Science Fellow (2026)
• Alex Zettl Graduate Student Award in Physics, UC Berkeley (2026)
• Jackson C. Koo Award, UC Berkeley (2026)
• Kavli ENSI Graduate Student Fellow (2023)
• Weiming Scholar, Peking University (2020)

Featured Results

Dipolar excitonic insulator in electron-hole bilayers

Establishment of equilibrium excitonic insulating phases through thermodynamic measurements and perfect Coulomb drag, demonstrating strongly correlated electron-hole pairing.

Perfect Coulomb drag and exciton transport (Science, 2025)

Excitonic quantum oscillations (Nature Materials, 2026)

Thermodynamics of correlated electron-hole fluids (Nature Communications, 2023)

Equilibrium fluids of excitonic ions and molecules

Demonstration of electrically tunable equilibrium fluids formed by charged interlayer trions and neutral trilayer biexcitons, establishing excitonic ions and excitonic molecules as interacting quasiparticles in strongly coupled electron-hole systems.

Electrically controlled interlayer trion fluid (Science, 2025)

Gate-tunable biexcitons in electron-hole-electron trilayers (under final editorial processing at Science)

Exciton crystal

Observation of an exciton crystal phase in a moiré excitonic insulator, revealing interaction-driven ordering of composite bosonic quasiparticles.

Exciton crystal in a moiré excitonic insulator (Nature Physics, 2026)

Two-component exciton condensate

Observation of a two-component exciton condensate in an equilibrium exciton fluid, revealing a spinor condensate order that can be switched among competing condensate states by a weak magnetic field.

Two-component exciton condensates (Nature, 2026)

Earlier Work

Interface phonons at the nanoscale

Direct measurement of phonon dispersion at interfaces using electron energy-loss spectroscopy with nanometer spatial resolution.

Measuring phonon dispersion at an interface (Nature, 2021)

Publications

^† equal contribution; ^‡ corresponding author

• Two-component exciton condensates in an electron–hole bilayer
  Ruishi Qi^†‡, Qize Li^†, Jiahui Nie, Ruichen Xia, Haleem Kim, Hyungbin Lim, Jingxu Xie, Takashi Taniguchi, Kenji Watanabe, Michael F. Crommie, Allan H. MacDonald, Feng Wang^‡
  Nature 654, 629–634 (2026)
• Gate-tunable biexcitons in electron-hole-electron trilayers
  Ruishi Qi^†‡, Qize Li^†, Zuocheng Zhang, Jingxu Xie, Zhiyuan Cui, Takashi Taniguchi, Kenji Watanabe, Michael F. Crommie, Feng Wang^‡
  Under final editorial processing at Science (2026)
• Understanding two-component spinor order in bilayer exciton condensates
  Ruishi Qi^‡, Qize Li, Jiahui Nie, Feng Wang^‡
  Under review at Physical Review Letters (2026)
• An exciton crystal in a moiré excitonic insulator
  Ruishi Qi^†, Qize Li^†, Haleem Kim, Jiahui Nie, Zuocheng Zhang, Ruichen Xia, Zhiyuan Cui, Jianghan Xiao, Takashi Taniguchi, Kenji Watanabe, Michael F. Crommie, Feng Wang^‡
  Nature Physics, 22, 514-520 (2026)

  Nature Reviews Materials Research Highlight Nature Physics News & Views
• Orbital dependent Coulomb drag in electron-hole bilayer graphene heterostructures
  Zuocheng Zhang^†‡, Ruishi Qi^†, Jingxu Xie, Qize Li, Takashi Taniguchi, Kenji Watanabe, Michael F. Crommie, Feng Wang^‡
  Physical Review Letters, 136, 126303 (2026)

  Editor's Suggestion
• Nature of emergent moiré excitations in MoSe2/WS2 moiré superlattices
  Zheyu Lu^†‡, Ruishi Qi^†, Rwik Dutta^†, Jingxu Xie, Jiahui Nie, Ziyu Wang, Yibo Feng, Woochang Kim, Kenji Watanabe, Takashi Taniguchi, Archana Raja, Mit H. Naik, Steven G. Louie, Feng Wang^‡
  Nano Letters 26 (12), 4096-4102 (2026)
• Competition between excitonic insulators and quantum Hall states in correlated electron-hole bilayers
  Ruishi Qi^†, Qize Li^†, Zuocheng Zhang, Jiahui Nie, Bo Zou, Zhiyuan Cui, Haleem Kim, Collin Sanborn, Sudi Chen, Jingxu Xie, Takashi Taniguchi, Kenji Watanabe, Michael F. Crommie, Allan H. MacDonald, Feng Wang^‡
  Nature Materials 25, 35–41 (2026)
• Electrically controlled interlayer trion fluid in electron-hole bilayers
  Ruishi Qi, Qize Li, Zuocheng Zhang, Sudi Chen, Jingxu Xie, Yunbo Ou, Zhiyuan Cui, David D. Dai, Andrew Y. Joe, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Alex Zettl, Liang Fu, Feng Wang^‡
  Science 390, 299–303 (2025)

  Science Perspective
• Perfect Coulomb drag and exciton transport in an excitonic insulator
  Ruishi Qi^†, Andrew Y. Joe^†‡, Zuocheng Zhang, Jingxu Xie, Qixin Feng, Zheyu Lu, Ziyu Wang, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Feng Wang^‡
  Science 388, 278–283 (2025)

  Journal Club for Condensed Matter Physics
• Thermodynamic behavior of correlated electron-hole fluids in van der Waals heterostructures
  Ruishi Qi^†, Andrew Y. Joe^†‡, Zuocheng Zhang, Yongxin Zeng, Tiancheng Zheng, Qixin Feng, Jingxu Xie, Emma Regan, Zheyu Lu, Takashi Taniguchi, Kenji Watanabe, Sefaattin Tongay, Michael F. Crommie, Allan H. MacDonald, Feng Wang^‡
  Nature Communications 14, 8264 (2023)
• Measuring phonon dispersion at an interface
  Ruishi Qi^†, Ruochen Shi^†, Yuehui Li, Yuanwei Sun, Mei Wu, Ning Li, Jinlong Du, Kaihui Liu, Chunlin Chen, Ji Chen, Feng Wang, Dapeng Yu, En-Ge Wang, Peng Gao^‡
  Nature 599, 399–403 (2021)
• Four-dimensional vibrational spectroscopy for nanoscale mapping of phonon dispersion in BN nanotubes
  Ruishi Qi^†, Ning Li^†, Jinlong Du, Ruochen Shi, Yang Huang, Xiaoxia Yang, Lei Liu, Zhi Xu, Qing Dai, Dapeng Yu, Peng Gao^‡
  Nature Communications 12, 1179 (2021)
• Probing far-infrared surface phonon polaritons in semiconductor nanostructures at nanoscale
  Ruishi Qi^†, Renfei Wang^†, Yuehui Li, Yuanwei Sun, Shulin Chen, Bo Han, Ning Li, Qing Zhang, Xinfeng Liu, Dapeng Yu, Peng Gao^‡
  Nano Letters 19, 5070–5076 (2019)
• Contactless cavity sensing of superfluid stiffness in atomically thin 4Hb-TaS2
  Trevor Chistolini^†, Ha-Leem Kim^†, Qiyu Wang^†, Su-Di Chen, Luke Pritchard Cairns, Ryan Patrick Day, Collin Sanborn, Hyunseong Kim, Zahra Pedramrazi, Ruishi Qi, Takashi Taniguchi, Kenji Watanabe, James G. Analytis, David I. Santiago, Irfan Siddiqi, Feng Wang^‡
  Physical Review Letters 137, 076002 (2026)
• Electron Microscopy Measurement of Picometer-Level Distortion Induced Local Phonons at a Defect
  Bo Han, Ruochen Shi, Huining Peng, Yingjie Lv, Ruishi Qi, Yuehui Li, Jingmin Zhang, Jinlong Du, Pu Yu, Peng Gao^‡
  Nano Letters 26 (4), 1449-1454 (2026)
• Tunable Interlayer Charge-transfer States in MoSe₂/WS₂ Moiré Superlattices
  Zheyu Lu^†‡, Jiahui Nie^†, Tianle Wang, Rwik Dutta, Ruishi Qi, Jingxu Xie, Can Uzundal, Jianghan Xiao, Ziyu Wang, Yibo Feng, Kenji Watanabe, Takashi Taniguchi, James R. Chelikowsky, Archana Raja, Steven G. Louie, Mit H. Naik, Michael P. Zaletel, Feng Wang^‡
  Under revision at Nature Communications; arXiv:2605.05571 (2026)
• Electrically controlled Heat Assisted Magnetic Recording in Intercalated 2D Magnets
  Josue Rodriguez, Ruishi Qi, Catherine Xu, Feng Wang, James G. Analytis, Hossein Taghinejad^‡
  Under revision at npj Spintronics; arXiv:2605.06645 (2026)
• Optical voltage profiling of 2D semiconductors via proximal exciton sensing
  Ha-Leem Kim^†, Hyungbin Lim^†, Yuanyi Yang, Ruishi Qi, Ruichen Xia, Can Uzundal, Takashi Taniguchi, Kenji Watanabe, Feng Wang^‡
  Submitted; arXiv:2608.18382 (2026)
• Terahertz electrodynamics in a zero-field Wigner crystal
  Su-Di Chen^‡, Ruishi Qi, Ha-Leem Kim, Qixin Feng, Ruichen Xia, Dishan Abeysinghe, Jingxu Xie, Takashi Taniguchi, Kenji Watanabe, Dung-Hai Lee, Feng Wang^‡
  Under review at Nature Physics; arXiv:2509.10624 (2025)
• Direct Measurement of Terahertz Conductivity in a Gated Monolayer Semiconductor
  Su-Di Chen, Qixin Feng, Wenyu Zhao, Ruishi Qi, Zuocheng Zhang, Dishan Abeysinghe, Can Uzundal, Jingxu Xie, Takashi Taniguchi, Kenji Watanabe, Feng Wang^‡
  Nano Letters 25 (19), 7998-8002 (2025)
• Measurement of far-infrared surface phonon polaritons in AlN nanowires via electron microscope
  Chao He, Ze Hua, Peiyi He, Ruishi Qi, Yuehui Li, Ruiwen Shao, Weikang Dong, Ruochen Shi, Yeliang Wang, Peng Gao^‡
  Chinese Physics B 35, 037901 (2025)
• Femtojoule All-optical Nonlinearity for Deep Learning with Incoherent Illumination
  Qixin Feng^†, Can B. Uzundal^†, Ruihan Guo, Collin Sanborn, Ruishi Qi, Jingxu Xie, Jianing Zhang, Junqiao Wu, Feng Wang^‡
  Science Advances 11, eads4224 (2025)
• Strongly confined Mid-infrared to Terahertz Phonon Polaritons in Ultra-thin SrTiO3
  Peiyi He^†, Jiade Li^†, Cong Li, Ning Li, Bo Han, Ruochen Shi, Ruishi Qi, Jinlong Du, Pu Yu, Peng Gao^‡
  Science Advances 11, eady7316 (2025)
• Single-dislocation phonons: atomic-scale measurement and their thermal properties
  Yue-Hui Li^†, Bo Han^†, Xiao-Long Yang, Rui-Lin Mao, Fa-Chen Liu, Ruo-Chen Shi, Rui-Shi Qi, Xiao-Rui Hao, Ning Li, Bing-Yao Liu, Xiao-Mei Li, Jin-Long Du, Ji Chen, Wu Li, Peng Gao^‡
  Chinese Physics Letters 42, 066302 (2025)
• Terahertz phonon engineering with van der Waals heterostructures
  Yoseob Yoon^‡, Zheyu Lu, Can Uzundal, Ruishi Qi, Wenyu Zhao, Sudi Chen, Qixin Feng, Woochang Kim, Mit H. Naik, Kenji Watanabe, Takashi Taniguchi, Steven G. Louie, Michael F. Crommie, Feng Wang^‡
  Nature 631, 771-776 (2024)
• Low Resistance Contact to P-type Monolayer WSe2
  Jingxu Xie, Zuocheng Zhang, Haodong Zhang, Vikram Nagarajan, Wenyu Zhao, Ha-Leem Kim, Collin Sanborn, Ruishi Qi, Sudi Chen, Salman Kahn, Kenji Watanabe, Takashi Taniguchi, Alex Zettl, Michael F. Crommie, James Analytis, Feng Wang^‡
  Nano Letters 24 (20), 5937-5943 (2024)
• Engineering correlated insulators in bilayer graphene with a remote Coulomb superlattice
  Zuocheng Zhang^†, Jingxu Xie^†, Wenyu Zhao, Ruishi Qi, Collin Sanborn, Shaoxin Wang, Salman Kahn, Kenji Watanabe, Takashi Taniguchi, Alex Zettl, Michael Crommie, Feng Wang^‡
  Nature Materials 23, 189-195 (2024)
• Atomic-scale observation of localized phonons at FeSe/SrTiO3 interface
  Ruochen Shi^†, Qize Li^†, Xiaofeng Xu, Bo Han, Ruixue Zhu, Fachen Liu, Ruishi Qi, Xiaowen Zhang, Jinlong Du, Ji Chen, Dapeng Yu, Xuetao Zhu, Jiandong Guo, Peng Gao^‡
  Nature Communications 15, 3418 (2024)
• Probing Hyperbolic Shear Polaritons in β-Ga2O3 Nanostructures Using STEM-EELS
  Zhenyu Zhang, Tao Wang, Hailing Jiang, Ruishi Qi, Yuehui Li, Jinlin Wang, Shanshan Sheng, Ning Li, Ruochen Shi, Jiaqi Wei, Fang Liu, Shengnan Zhang, Xiaoqing Huo, Jinlong Du, Jingmin Zhang, Jun Xu, Xin Rong, Peng Gao, Bo Shen, Xinqiang Wang^‡
  Advanced Materials 36, 2204884 (2024)
• Nanoscale Localized Phonons at Al2O3 Grain Boundaries
  Jingyuan Yan, Ruochen Shi, Jiake Wei, Yuehui Li, Ruishi Qi, Mei Wu, Xiaomei Li, Bin Feng, Peng Gao, Naoya Shibata, Yuichi Ikuhara^‡
  Nano Letters 24 (11), 3323-3330 (2024)
• Four-dimensional electron energy-loss spectroscopy
  Mei Wu, Ruochen Shi, Ruishi Qi, Yuehui Li, Jinlong Du, Peng Gao^‡
  Ultramicroscopy 253, 113818 (2023)
• Effects of localized interface phonons on heat conductivity in ingredient heterogeneous solids
  Mei Wu^†, Ruochen Shi^†, Ruishi Qi^†, Yuehui Li, Tao Feng, Bingyao Liu, Jingyuan Yan, Xiaomei Li, Zhetong Liu, Tao Wang, Tongbo Wei, Zhiqiang Liu, Jinlong Du, Ji Chen, Peng Gao^‡
  Chinese Physics Letters 40 (3), 036801 (2023)
• Hyperbolic whispering-gallery phonon polaritons in boron-nitride nanotubes
  Xiangdong Guo^†, Ning Li^†, Xiaoxia Yang^‡, Ruishi Qi, Chenchen Wu, Ruochen Shi, Yuehui Li, Yang Huang, F. Javier García de Abajo, En-Ge Wang, Peng Gao, Qing Dai^‡
  Nature Nanotechnology 18, 529-534 (2023)
• Phonon transition across an isotopic interface
  Ning Li^†, Ruochen Shi^†, Yifei Li^†, Ruishi Qi, Fachen Liu, Xiaowen Zhang, Zhetong Liu, Yuehui Li, Xiangdong Guo, Kaihui Liu, Ying Jiang, Xin-Zheng Li, Ji Chen, Lei Liu, En-Ge Wang, Peng Gao^‡
  Nature Communications 14, 2382 (2023)
• Atomic-scale probing of heterointerface phonon bridges in nitride semiconductor
  Yue-Hui Li, Rui-Shi Qi, Ruo-Chen Shi, Jian-Nan Hu, Zhe-Tong Liu, Yuan-Wei Sun, Ming-Qiang Li, Ning Li, Can-Li Song, Lai Wang, Zhi-Biao Hao, Yi Luo, Qi-Kun Xue, Xu-Cun Ma, Peng Gao^‡
  Proceedings of the National Academy of Sciences 119 (8), e2117027119 (2022)
• Dynamics of Polar Skyrmion Bubbles under Electric Fields
  Ruixue Zhu^†, Zhexin Jiang, Xinxin Zhang, Xiangli Zhong, Congbing Tan, Mingwei Liu, Yuanwei Sun, Xiaomei Li, Ruishi Qi, Ke Qu, Zhetong Liu, Mei Wu, Mingqiang Li, Boyuan Huang, Zhi Xu, Jinbin Wang, Kaihui Liu, Peng Gao^‡, Jie Wang, Jiangyu Li, Xuedong Bai
  Physical Review Letters 129 (10), 107601 (2022)
• Studying Plasmon Dispersion of MXene for Enhanced Electromagnetic Absorption
  Xiangdong Guo^†, Ning Li^†, Chenchen Wu, Xiaokang Dai, Ruishi Qi, Tianyu Qiao, Tuoyi Su, Dandan Lei, Nishuang Liu, Jinlong Du, Enge Wang, Xiaoxia Yang, Peng Gao, Qing Dai^‡
  Advanced Materials 34 (33), 2270237 (2022)
• Charge Transfer Dynamics in MoSe2/hBN/WSe2 Heterostructures
  Yoseob Yoon, Zuocheng Zhang, Ruishi Qi, Andrew Y. Joe, Renee Sailus, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Feng Wang^‡
  Nano Letters 22 (24), 10140-10146 (2022)
• Direct observation of highly confined phonon polaritons in suspended monolayer hexagonal boron nitride
  Ning Li^†, Xiangdong Guo^†, Xiaoxia Yang^‡, Ruishi Qi, Tianyu Qiao, Yifei Li, Ruochen Shi, Yuehui Li, Kaihui Liu, Zhi Xu, Lei Liu, F. Javier García de Abajo, Qing Dai, En-Ge Wang, Peng Gao^‡
  Nature Materials 20, 43-48 (2021)
• Anisotropic moiré optical transitions in twisted monolayer/bilayer phosphorene heterostructures
  Shilong Zhao^†, Erqing Wang^†, Ebru Alime Üzer, Shuaifei Guo, Ruishi Qi, Junyang Tan, Kenji Watanabe, Takashi Taniguchi, Tom Nilges, Peng Gao, Yuanbo Zhang, Hui-Ming Cheng, Bilu Liu, Xiaolong Zou, Feng Wang^‡
  Nature Communications 12, 3947 (2021)
• Broad-Spectral-Range Sustainability and Controllable Excitation of Hyperbolic Phonon Polaritons in α-MoO3
  Weikang Dong^†, Ruishi Qi^†, Tiansheng Liu, Yi Li, Ning Li, Ze Hua, Zirui Gao, Shuyuan Zhang, Kaihui Liu, Jiandong Guo, Peng Gao^‡
  Advanced Materials 32, 2002014 (2020)
• Manipulation of surface phonon polaritons in SiC nanorods
  Yuehui Li, Ruishi Qi, Ruochen Shi, Ning Li, Peng Gao^‡
  Science Bulletin 65 (10), 820-826 (2020)
• Probing lattice vibrations at SiO2/Si surface and interface with nanometer resolution
  Yue-Hui Li^†, Mei Wu^†, Rui-Shi Qi, Ning Li, Yuan-Wei Sun, Cheng-Long Shi, Xue-Tao Zhu, Jian-Dong Guo, Da-Peng Yu, Peng Gao^‡
  Chinese Physics Letters 36 (2), 026801 (2019)

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