Javier Sanchez-Yamagishi
Assistant Professor of Physics and Astronomy UC Irvine
- Irvine CA
Javier Sanchez-Yamagishi is an experimental physicist who discovers new approaches to quantum physics for the development of new devices.
Media
Social
Biography
Areas of Expertise
Accomplishments
National Science Foundation Graduate Research Fellowship
2008-2011
Harvard Quantum Optics Center Postdoctoral Fellowship
2015-2017
National Academy of Sciences Kavli Frontiers Fellow
2019
National Science Foundation Career Award
2021
UCI Hellman Fellowship
2024
Education
Rutgers University
B.S.
Physics
2008
Massachusetts Institute of Technology
Ph.D.
Physics
2015
Media Appearances
Metal sheets, ultra-thin feats: are China’s 2D metals the future of electronics?
South China Morning Post online
2025-03-16
Javier Sanchez-Yamagishi, a specialist in two-dimensional (2D) materials at the University of California, Irvine, said that while the Chinese team was not the first to produce atomically thin metals, their results stood out because the new method produces “large-scale, truly 2D metals” compared to previous techniques.
Articles
Controllable strain-driven topological phase transition and dominant surface-state transport in HfTe5
Nature CommunicationsJinyu Liu, Yinong Zhou, Sebastian Yepez Rodriguez, Matthew A. Delmont, Robert A. Welser, Triet Ho, Nicholas Sirica, Kaleb McClure, Paolo Vilmercati, Joseph W. Ziller, Norman Mannella, Javier D. Sanchez-Yamagishi, Michael T. Pettes, Ruqian Wu & Luis A. Jauregui
2024
The fine-tuning of topologically protected states in quantum materials holds great promise for novel electronic devices. However, there are limited methods that allow for the controlled and efficient modulation of the crystal lattice while simultaneously monitoring the changes in the electronic structure within a single sample. Here, we apply significant and controllable strain to high-quality HfTe5 samples and perform electrical transport measurements to reveal the topological phase transition from a weak topological insulator phase to a strong topological insulator phase.
Electrically driven amplification of terahertz acoustic waves in graphene
Nature CommunicationsAaron H. Barajas-Aguilar, Jasen Zion, Ian Sequeira, Andrew Z. Barabas, Takashi Taniguchi, Kenji Watanabe, Eric B. Barrett, Thomas Scaffidi & Javier D. Sanchez-Yamagishi
2024
In graphene devices, the electronic drift velocity can easily exceed the speed of sound in the material at moderate current biases. Under these conditions, the electronic system can efficiently amplify acoustic phonons, leading to an exponential growth of sound waves in the direction of the carrier flow. Here, we show that such phonon amplification can significantly modify the electrical properties of graphene devices. We observe a superlinear growth of the resistivity in the direction of the carrier flow when the drift velocity exceeds the speed of sound — resulting in a sevenfold increase over a distance of 8 µm.
Exceptional electronic transport and quantum oscillations in thin bismuth crystals grown inside van der Waals materials
Nature MaterialsLaisi Chen, Amy X. Wu, Naol Tulu, Joshua Wang, Adrian Juanson, Kenji Watanabe, Takashi Taniguchi, Michael T. Pettes, Marshall A. Campbell, Mingjie Xu, Chaitanya A. Gadre, Yinong Zhou, Hangman Chen, Penghui Cao, Luis A. Jauregui, Ruqian Wu, Xiaoqing Pan & Javier D. Sanchez-Yamagishi
2024
Confining materials to two-dimensional forms changes the behaviour of the electrons and enables the creation of new devices. However, most materials are challenging to produce as uniform, thin crystals. Here we present a synthesis approach where thin crystals are grown in a nanoscale mould defined by atomically flat van der Waals (vdW) materials. By heating and compressing bismuth in a vdW mould made of hexagonal boron nitride, we grow ultraflat bismuth crystals less than 10 nm thick. Due to quantum confinement, the bismuth bulk states are gapped, isolating intrinsic Rashba surface states for transport studies.
Manipulating moires by controlling heterostrain in van der Waals devices
Nano LettersIan Sequeira, Andrew Z. Barabas, Aaron H Barajas-Aguilar, Michaela G Bacani, Naoto Nakatsuji, Mikito Koshino, Takashi Taniguichi, Kenji Watanabe & Javier D. Sanchez-Yamagishi
2024
Van der Waals (vdW) moirés offer tunable superlattices that can strongly manipulate electronic properties. We demonstrate the in situ manipulation of moiré superlattices via heterostrain control in a vdW device. By straining a graphene layer relative to its hexagonal boron nitride substrate, we modify the shape and size of the moiré. Our sliding-based technique achieves uniaxial heterostrain values exceeding 1%, resulting in distorted moirés values that are larger than those achievable without strain. The stretched moiré is evident in transport measurements, resulting in shifted superlattice resistance peaks and Landau fans, consistent with an enlarged superlattice unit cell.
Metals squeezed to thickness of just two atoms
NatureJavier D. Sanchez-Yamagishi
2025
In contrast to van der Waals materials, metallic elements generally do not have layered structures that can be easily peeled apart. Instead, 2D metals have been prepared in vacuum chambers by spraying a layer of atoms onto a substrate (see refs 6 and 7, for example). Studies of these materials7, 8 have enabled the observation of some of the predicted 2D phenomena. The challenge is that these approaches produce only nanometre-scale irregular ‘islands’ of 2D crystals, which are too small to use in electronic devices. The substrates also cause difficulties by interacting with the 2D metals in ways that prevent the electronic properties of the 2D materials from being properly observed or measured. Zhao and colleagues’ approach resolves many of these challenges.
