A5068924105- Topological Materials and Phenomena
- Photonic and Optical Devices
- Quantum Mechanics and Non-Hermitian Physics
- Advanced Condensed Matter Physics
- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum many-body systems
- Quantum and electron transport phenomena
- Quantum optics and atomic interactions
- Organic and Molecular Conductors Research
- Advanced Fiber Laser Technologies
- Photorefractive and Nonlinear Optics
- Quantum Information and Cryptography
- Nonlinear Photonic Systems
- Graphene research and applications
- Strong Light-Matter Interactions
- 2D Materials and Applications
- Stellar, planetary, and galactic studies
- Advanced Chemical Physics Studies
- Phase-change materials and chalcogenides
- Quantum, superfluid, helium dynamics
- Semiconductor Quantum Structures and Devices
- Photonic Crystals and Applications
- Terahertz technology and applications
- Material Properties and Applications
University of California, Los Angeles
2023-2025
Physical Sciences (United States)
2024
Harvard University
2022-2023
ETH Zurich
2018-2020
Abstract Topological Insulators are a novel state of matter where spectral bands characterized by quantized topological invariants. This unique nonlocal property commonly manifests through exotic bulk phenomena and corresponding robust boundary effects. In our work we study system the associated with non-quantized indices, but nevertheless possess states. We present theoretical analysis, show that square Hamiltonian exhibits indices. The findings experimentally demonstrated using photonic...
Modern technological advances allow for the study of systems with additional synthetic dimensions. Using such approaches, higher-dimensional physics that was previously deemed to be purely theoretical interest has now become an active field research. In this work, we derive from first principles using a semiclassical equation motions approach, bulk response six-dimensional Chern insulator. We find in system quantized appears quantization originating topological index -- 3rd number. Alongside...
Topological insulators are materials with spectral bands associated an integer-valued index, manifesting through quantized bulk phenomena and robust boundary effects. In this Rapid Communication, we demonstrate that higher-order topological descendants from a high-dimensional chiral semimetal. Specifically, apply dimensional reduction to ancestor four-dimensional Chern insulator, obtain two-dimensional (2D) second-order when the former becomes chiral. Correspondingly, derive charge...
Reciprocal and nonreciprocal effects in dielectric magnetic materials provide crucial information about the microscopic properties of electrons. However, experimentally distinguishing two has proven to be challenging, especially when associated are extremely small. To this end, we propose a contactless detection using cross-cavity device where material interest is placed at its center. We show that optical material, such as Kerr Faraday rotation, or birefringence, manifest coupling between...
Due to the chiral anomaly, Weyl semimetals can exhibit a signature topological magnetoelectric response known as an axion term which is determined by microscopic band structure. In presence of strong interactions fermions may form condensate, with intrinsic dynamics and fluctuations associated condensate phase producing dynamical contribution response. Here we show that imbalance in density right- left-handed electrons drives instability towards finite momentum leads We derive...
Introducing internal degrees of freedom in the description topological insulators has led to a myriad theoretical and experimental advances. Of particular interest are effects periodic perturbations, either time or space, as they considerably enrich variety electronic responses, with examples such Thouless's charge pump its higher dimensional cousins, or, higher-order insulators. Here, we develop semiclassical approach transport accumulation general spinor freedom, physical spin, valley,...
Topological Insulators are a novel state of matter where spectral bands characterized by quantized topological invariants. This unique non-local property commonly manifests through exotic bulk phenomena and corresponding robust boundary effects. In our work, we report new type insulator exhibiting with non-quantized properties, but quantization that arises in system the square Hamiltonian is taken. We provide thorough theoretical analysis as well an experimental demonstration based on...
Out-of-equilibrium effects provide an elegant pathway for probing and understanding the underlying physics of topological materials. In particular, controlling electronic band structure properties using ultrafast optical pulses has shown promise creating exotic states matter. Of recent interest is renormalization in Dirac Weyl semimetals as it leads to direct physical observables through enhancement effective mass or shift resonant energies. Here we experimental theoretical signatures...
<title>Abstract</title> Reciprocal and nonreciprocal effects in dielectric magnetic materials provide crucial information about the microscopic properties of electrons. However, experimentally distinguishing two has proven to be challenging, especially when associated are extremely small. To this end, we propose a contact-less detection using cross-cavity device where material interest is placed at its centre. We show that optical material, such as Kerr Faraday rotation, or, birefringence,...
Graphene nanoribbons (GNRs) are unique quasi-one-dimensional (1D) materials that have garnered a lot of research interest in the field topological insulators. While phases exhibited by GNRs primarily governed their chemical structures, ability to externally control these is crucial for potential utilization quantum electronics and spintronics. Here we propose class featured mirror symmetry four zigzag segments unit cell has properties induced controlled an applied electric field. Their band...
Magneto-Raman spectroscopy reveals magnetic ordering dependent helical phonon vibration modes in FM- and AFM-EuCd 2 As samples below their critical temperatures. While AFM-sample has the same spectra co-circular polarizations, FM-sample different degree of circular polarization.
An amendment to this paper has been published and can be accessed via a link at the top of paper.
Time-resolved dynamics in charge-density-wave materials have revealed interesting out-of-equilibrium electronic responses. However, these are typically only performed a single material possessing CDW. As such, it is challenging to separate subtle effects originating from the Here, we report on ultrafast of GdSbxTe2–x–δ series where EF can be tuned, resulting change an undistorted tetraganal phase CDW with wavevector that depends x. Using mid-infrared, near-infrared, and visible excitation,...
We report a new type of insulator that exhibits spectral bands with non-quantized topological properties. Furthermore, quantisation manifests itself upon squaring the Hamiltonian. experimentally verify our claims by using photonic Aharonov-Bohm cages.
Time-resolved dynamics in charge-density-wave materials have revealed interesting out-of-equilibrium electronic responses. However these are typically only performed a single material possessing CDW. As such, it is challenging to separate subtle effects originating from the Here, we report on ultrafast of GdSb$_{x}$Te$_{2-x-\delta}$ series where E$_{F}$ can be tuned, resulting change an undistorted tetraganal phase CDW with wavevector that depends $x$. Using mid-infrared, near-infrared, and...
The unusual magnetoelectric transport present in Weyl semimetals can be compactly understood as manifestations of an underlying axion field, which itself is determined by the microscopic band structure. couples nonlinearly to electric and magnetic fields possesses a signature topological response, leading modified form Maxwell's equations known electrodynamics. Axions are naturally relating separation nodes energy crystal momentum. In presence strong interactions, charge density-wave (CDW)...
<title>Abstract</title> The unusual magnetoelectric transport present in Weyl semimetals can be compactly understood as manifestations of an underlying axion field, which itself is determined by the microscopic band structure. couples nonlinearly to electric and magnetic fields possesses a signature topological response, leading modified form Maxwell’s equations known electrodynamics. Axions are naturally relating separation nodes energy crystal momentum. In presence strong interactions,...
Reciprocal and nonreciprocal effects in dielectric magnetic materials provide crucial information about the microscopic properties of electrons. However, experimentally distinguishing two has proven to be challenging, especially when associated are extremely small. To this end, we propose a contact-less detection using cross-cavity device where material interest is placed at its centre. We show that optical material, such as Kerr Faraday rotation, or, birefringence, manifest coupling between...
We report a new type of insulator that exhibits spectral bands with non-quantized topological properties. Furthermore, quantisation manifests itself upon squaring the Hamiltonian. experimentally verify our claims by using photonic Aharonov-Bohm cages. © 2019 The Author(s)
Topological insulators have to date seen a variety of manifestations. All available realizations topological insulators, however, share common feature: their spectral bands are attributed with nonlocal index that is quantized. In this work, we report new type insulator exhibiting nonquantized indices, yet robust boundary states. We provide theoretical analysis based on the quantization indices in corresponding system where square Hamiltonian taken and exemplify general paradigm using...
In many applications, topological effects can be characterized by a quantized invariant [1]. this work, we investigate new type of insulator that stands apart from formalism, since it exhibits spectral bands with non-quantized properties. As turns out, system nevertheless reconciled the existing paradigm, quantization established squaring Hamiltonian Fig. 1(b).