Department of Physics,National Taiwan University

• Aug 2021 –present      Assistant Professor, Department of Physics, National Taiwan University
• Nov 2019 –June 2021  Research Fellow, Institut für Experimentelle und Angewandte Physik, University of Regensburg
• Jan 2016 – Sept 2019   Research Fellow, Department of Physics , University of California Berkeley
• June 2013-Dec 2015    Research Fellow, Cavendish Laboratory, University of Cambridge 

• 2021    Yushan Young Fellow, Ministry of Education, Taiwan 
• 2020    Columbus Research Grant holder, Ministry of Science and Technology, Taiwan 
• 2013    Young Scientist Award, European Materials Research Society (EMRS) 
• 2012    Nicholas Kurti Prize for Distinguished Postgraduate Work, University of Oxford 
• 2011    David Ryan Prize for Distinguished Postgraduate Work, University of Oxford 

Teaching

General Physics for 1^st year undergraduate courses

Research area:

Ultrafast nonlinear optical microscopy, low-dimensional quantum materials, light-matter interactions

超快非線性光學顯微鏡、低維量子材料、光與物質相互作用

Research:

My research focus on light-matter interaction in the low-dimensional quantum material heterostructures. Over the past few years, we have developed various ultrafast nonlinear optical microscopic techniques and established the significance of ultrafast optical spectroscopy in revealing the unique quantum dynamics in various low-dimensional systems, such as semiconducting nanowires, organic molecules, and atomically thin quantum materials. Recently, the ability to isolate the materials into atomically thin layer in various van der Waals materials, such as graphene and transition metal dichalcogenides (TMD), has provided a unique platform to explore various light-driven quantum phenomena in a custom-tailored quantum system. By improving the sample qualities and experimental approaches, our future research will focus on both fundamental quantum science research and development of nanoscale quantum technology through investigating:

1. Many-body interactions: Reduced dimensionality leads to strong confinement of electronic wavefunction in atomically thin 2D materials and greatly enhances the electron-electron interaction. Engineering the atomic interface of 2D heterostructures can lead to unique light-matter interactions and exotic properties that are not so obvious or not even seen in the bulk, such as prominent many-body biexciton states, Mott insulator, Wigner Crystal phase, and charge density wave. We aim to improve the sample quality and develop optical measurements to realize the unique quantum states of matters arise from twisting the atomic interface of 2D heterostructures.
2. Ultrafast manipulation of quantum states of matters: The combination of prominent light-matter interaction, spin-orbit coupling and strong confinement of electronic wavefunctions in 2D heterostructure provide a unique platform to realize all-optical manipulation of electronic states, spin, valley, phonon and their interplays in the system, with application relevant to the quantum computing and information processing. We aim to advance the ultrafast nonlinear optical microscopy based on phase-locked femtosecond laser pulses to explore the coherent control of quantum states of matters, paving way to realize the ultimate limits of electron dynamics in the quantum devices.
3. Light-induced quantum phase transitions: By advancing the ultrafast THz spectroscopy, we aim to understand and control the microscopic interplay between elementary degrees of freedom that governing the quantum phase transitions in atomically thin quantum materials, providing new platforms to design quantum systems with novel functionalities. In-particular, as the materials are thinned down to monolayer, the interplays among electronic wavefunction, lattice, and environments can give rise to various quantum ground states. Even more exciting is the ability to engineer the electronic wavefunction through the highly flexible interlayer proximity control, electrostatic doping and moiré superlattice engineering. We are interested to explore the novel light-induced quantum phase transition in these systems using intense fs-laser pulses.

As the essential toolbox, our laboratory develops ultrafast optical microscopy based on highly-intense ultrashort laser pulses with energy spans from visible to THz. Similarly, to an extremely slow-motion camera, our approaches enable the simultaneous observation and control of the elementary quantum dynamics on the femtosecond timescale (1fs = 10^-15s), providing new physical insights on the properties of quantum materials stroboscopically that are otherwise impossible using other techniques. Exploiting the quantum physics and optical phenomena in the atomically thin 2D material heterostructures provide exciting pathways to implement these materials as building blocks in quantum optoelectronics, quantum computing and quantum information technology.

We welcome postdocs, graduate and undergraduate students interested in ultrafast optics, quantum materials, nanophotonics and nonlinear optics to join our team. We provide highly interactive and creative working environment for you to achieve highest scientific achievement. Please send email to chawkyong@phys.ntu.edu.tw to inquire.

1. Valley-Dependent Exciton Fine Structure and Autler-Townes Doublets from Berry Phases in Monolayer MoSe₂
   Chaw K. Yong*⁺, M. Iqbal Bakti Utama⁺, Chin Shen Ong, Ting Cao, Emma C. Regan, Jason Horng, Yuxia Shen, Hui Cai, Kenji Watanabe, Takashi Taniguchi, Sefaattin Tongay, Hui Deng, Alex Zettl, Steven G. Louie, Feng Wang*
   Nature Materials, vol. 18, pp. 1065, 2019 [doi]

2. Biexcitonic Optical Stark Effects in Monolayer Molybdenum Diselenide
   Chaw K. Yong*⁺, J. Horng⁺, Y. Shen, H. Cai, A. Wang, C. Yang, C. Lin, K. Watanabe, T. Taniguchi, S. Tongay, F. Wang*
   Nature Physics, vol. 14, pp. 1092, 2018 [doi]

3. Proximity control of the interlayer exciton-phonon hybridization in van der Waals heterostructures  
   Philipp Merkl⁺, Chaw K. Yong⁺*, M. Liebich, I. Hoffmann, E. Malic, R. Huber*
   Nature Communication, vol 12, pp. 1719, 2021 [doi]

4. Twist-tailoring Coulomb correlation in van der Waals homobilayers
   P. Merkl, F. Mooshammer, S. Brem, A. Girnghuber, K-Q Lin, L. Weigl, Chaw K. Yong, R. Gillen, J. Maultzsch, J. M. Lupton, E. Malic*, R. Huber*
   Nature Communication, vol. 11, pp. 2167, 2020 [doi]

5. The Entangled Triplet Pair State in Acene and Heteroacene Materials
   Chaw K. Yong*, A. Musser, S. L. Bayliss, S. Lukman, H. Tamaru, O. Bubnova, R. K. Hallani, A. Meneau, R. Resel, M. Maruyama, S. Hotta, L. M. Herz, D. Beljonne, J. E. Anthony, J. Clarke*, H. Sirringhaus*
   Nature Communication, vol. 8, pp. 15953, 2017 [doi]

6. Ultrafast delocalization of excitation in synthetic light-harvesting nanorings
   Chaw K. Yong, W. H. Chen, D. V. Kondratuk, P. Parkinson, A. Stannard, A. Summerfield, J. K. Sprafke, M. O'Sullivan, P. H. Beton, H. L. Anderson, and L. M. Herz*
   Chemical Science, vol. 6, pp. 181, 2014. [doi]

7. Direct Observation of Charge-Carrier Heating at WZ-ZB Type-II InP Nanowire Heterojunctions
   Chaw K. Yong, J. L. Wong, H. J. Joyce, Q. Gao, H. H. Tan, C. Jagadish, M. B. Johnston, and L. M. Herz*
   Nano Letters, vol. 13, pp. 4280, 2013. [doi]

8. Strong Carrier Lifetime Enhancement in GaAs Nanowires by Semiconducting Polymers in Type-II Heterojunctions
   Chaw K. Yong, K. Noori, Q. Gao, H. J. Joyce, H. H. Tan, C. Jagadish, F. Giustino, M. B. Johnston, and L. M. Herz*
   Nano Letters, vol. 12, pp. 6293, 2012. [doi]

9. High-capacity hydrogen storage in lithium and sodium amidoboranes
   Z. Xiong, Chaw K. Yong, G. Wu, P. Chen*, W. Shaw, A. Karkamkar, T. Autrey, M. O. Jones, S. M. Johnson, P. P. Edwards, and W. I. F. David Nature Materials, vol. 7, pp. 138-141, 2007 [doi]