Events - Materials
Event Record
Invited Speaker:
Dr. Bill Phillips, Nobel Laureate,University of Maryland
Laurie Locascio, VP for Research; University of Maryland
Curious about the buzz around quantum, but don’t really understand what the big deal is? Want to understand how the quantum revolution applies to you but don’t have a background in physics?
If so, please join the Mid-Atlantic Quantum Alliance (MQA) for a fireside chat between University of Maryland’s Vice President for Research, Dr. Laurie Locascio, and Nobel Laureate Dr. Bill Phillips. Dr. Phillips is a renowned science communicator in addition to being a leading scientist, and currently serves as a NIST Fellow and a University of Maryland Distinguished University Professor. This fireside chat will include a discussion of Dr. Phillips’ Nobel journey, a basic introduction to quantum physics, and answers to burning questions about the promise of emerging quantum technologies.
This fireside chat will be the first in a series of MQA virtual events that will dive more deeply into the remarkable capabilities that advances in quantum are unlocking for computing, sensing and ultra-secure communications — and how these will help to address real-world challenges. This MQA introductory series will help to connect potential customers and end-users with the research community to accelerate the innovation of quantum products that are responsive to actual needs and deliver value. To get more
information about these events, please click the RSVP link to sign up for
the mailing list or email Dr. John Sawyer (jsawyer2@umd.edu).
About the MQA: The Greater National Capital Region is one of the leading quantum powerhouses in the world; the Mid-Atlantic Quantum Alliance (MQA) brings the region’s extraordinary capabilities across academia, industry, non-profits, and government together to build a vibrant ecosystem that accelerates quantum innovation and impact. QSEC represents Mason as a founding and active member of the MQA.
Title: Tunneling into emergent topological matter
Speaker: Dr. Jiaxin Yin, Department of Physics, Princeton University
Abstract: The search for topological matter is evolving towards strongly interacting systems including magnets and superconductors, where novel effects emerge from the quantum level interplay between geometry, correlation, and topology. Equipped with unprecedented spatial resolution, high precision electronic detection and magnetic tunability, scanning tunneling microscopy has become a powerful tool to probe and discover the emergent topological matter. In this talk, I will discuss the proof-of-principle methodology applied to study the quantum topology in this discipline, with particular attention to studies performed under a tunable vector magnetic field, which is a relatively new direction of recent focus. I then project the future possibilities for tunnelling methods in providing new insights into topological matter.
Time: Nov 16, 2020 03:00 PM Eastern Time (US and Canada)
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https://gmu.zoom.us/j/93395778828?pwd=cU41REdZOEgwNWlXSlQzakJCUG5aZz09
Meeting ID: 933 9577 8828
Passcode: 639306
Key references:
- Jia-Xin Yin et al. Nature 583, 533-536 (2020).
- Jia-Xin Yin et al. Nature 562, 91-95 (2018).
- Jia-Xin Yin et al. Nature Physics 15, 443–448 (2019).
- Jia-Xin Yin et al. Nature Physics 11, 543 (2015).
- Jia-Xin Yin et al. Phys. Rev. Lett. 123, 217004 (2019).
- Jia-Xin Yin et al. Nature Communications 11, 4003 (2020).
- Jia-Xin Yin et al. Nature communications 11, 4415 (2020).
Brief CV of Dr. Jiaxin Yin:
Dr. Jiaxin Yin is currently a Postdoctoral Researcher in Prof. Zahid Hasan’s team in Princeton University, USA, and focuses on the scanning tunneling microscopy of emergent topological matter, including topological magnets and superconductors. He received his Ph.D. degree in 2016 from Institute of Physics, CAS, under Prof. Hong Ding and Prof. Shuheng Pan. In 2015, he observed a Majorana-like zero-energy mode in Fe(Te,Se), which simulated theoretical and experimental confirmation of nontrivial topology in iron-based superconductors. Recently, he has developed vector magnetic field based scanning tunneling microscopy technique to observe Chern toplogical phases and many-body effects in several quantum magnets.
Title: Magnetism in flatland
Speaker: Dr. Antia Botana, Arizona State University
Abstract: Spontaneous magnetic order is a routine instance in three-dimensional (3D) materials but for a long time, it remained elusive in the 2D world. Recently, the first examples of 2D van der Waals crystals with magnetic order at the monolayer level, either antiferromagnetic or ferromagnetic, have been reported. In this talk, I will describe the state of the art of the nascent field of magnetic 2D materials (focusing particularly on theoretical aspects), as well as challenges and some of the many different promising directions for future work.
Bio: Antia Botana is an assistant professor in the Department of Physics at Arizona State University. She got her PhD at the University of Santiago de Compostela, Spain. Prior to joining ASU, she was a postdoc at Argonne National Lab and at the University of California, Davis. Her research employs density functional theory to direct the computational design of materials with novel functionalities. She works on topics ranging from superconductivity to frustrated magnetism, thermoelectricity, and confinement effects in nanostructures.
Time: Nov 30, 2020 03:00 PM Eastern Time (US and Canada)
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https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: correlation between the Gini index and the observed prosperity
Speaker: Dr. Igor Mazin, GMU
Time: January 11, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract: Research about how taxation affects market economy by use a mathematical model to analyze CIA database, with a counterintuitive conclusion that too little taxation is as harmful to the economy as too much of it.
https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: Quantum Biosensing
Speaker: Dr. Rob Cressman, GMU
Time: January 18, 2021 03:00 PM Eastern Time (US and Canada)
Abstract: The creation of new two-dimensional materials has enabled the realization of novel physical states and interactions. These new materials could provide biomedical researchers more sensitive and specific tools to investigate the molecules and fields that support biological activity. However, there exist a number of hurdles between the creation of a novel substrate and a functional sensing platform, including probe creation, delivery, and readout. I will focus on potential strategies to overcome these obstacles in order to construct a pipeline for novel sensor development. The talk is intended to act as a seed for further discussions into the applications of quantum materials in biology.
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Title: Condense Matter Physics Seminar: Chirality-assisted vortex spin and toroidal moment in a triangular magnet, by Dr. Lei Ding of ORNL
Speaker: Dr. Lei Ding, Oak Ridge National Laboratory
Time: January 25, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract:
A toroidal dipole moment appears independent of the electric and magnetic dipole moment in the multipole expansion of electrodynamics. It arises naturally from vortex-like arrangements of spins. Observing and controlling spontaneous long-range orders of toroidal moments are highly promising for spintronics but remain challenging. In this talk, I present that a vortex-like spin configuration harboring a staggered arrangement of toroidal moments, a ferritoroidal state, is realized in a chiral triangular-lattice magnet BaCoSiO4. Upon applying a magnetic field, we observe multi-stair toroidal transitions correlating directly with metamagnetic transitions. We establish a first-principles microscopic Hamiltonian that explains both the formation of toroidal states and the metamagnetic toroidal transition as a combined effect of the magnetic frustration and the Dzyaloshinskii-Moriya interactions allowed by the crystallographic chirality.
Brief biography:
Lei Ding received his PhD degree from the Université Grenoble Alpes & Institut Néel, France, in Physics in 2016. Prior to joining the ORNL as a postdoc researcher, he was the Rutherford International fellow at the ISIS neutron and muon source, UK. His research interest lies in condensed matter physics with a particular focus on the study of emergent orders and excitations from the interplay between spin, charge, orbital, topology and lattice in novel materials including frustrated magnets, multiferroics and magnetic topological insulators.
Title: Finding Structural Order in Disordered Materials
Speaker: Dr. Howard Sheng, GMU
Time: January 11, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract: Disordered materials are ubiquitous in nature, ranging from liquids, glasses to complex structures such as proteins and biopolymers. Unlike crystals, disordered materials lack the long-range periodicity that defines crystals, which makes it extremely difficult to describe the atomic-level structures. Nonetheless, the atoms in disordered materials are not completely random, there is certain structural order hidden in the disordered systems. Therefore, unraveling structure ordering in disordered systems is key to understanding, utilizing, and designing disordered materials. In this talk, I will review several types of structural order we discovered in amorphous solids and liquids, achieved by combining advanced computational approaches and experimental characterization. At last, I will focus on our recent work on the structural ordering and phase transitions in group IV elements. If time permits, I will highlight a new type of structural order in the form of paracrystals in an amorphous diamond.
https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: Condense Matter Physics Seminar: Formation of Paracrystalline Diamond
Speaker: Dr. Howard Sheng, George Mason University
Time: February 1, 2021 03:00 PM Eastern Time (US and Canada)
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Title: Understanding the Properties of Inorganic-Organic Hybrid Nanoparticles for Materials Development
Speaker: Dr. Andre Clayborne, GMU
Time: January 11, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract: Inorganic-Organic Hybrid Nanoparticles combine a metal inorganic core with an organic exterior that can range in size and composition. These nanoparticles represent an interesting state of matter with unique properties. Though the properties can change with composition and size, a fundamental understanding must be ascertained to employ them in materials. I will discuss our work investigating the fundamental chemistry and physics of a series of inorganic-organic hybrid nanoparticles. Using a combination of computational methods along with collaboration with experimentalist, insight into the structure-property relationship for aluminum, copper and gold hybrid nanoparticles has been gained. ReaxFF-MD has provided insight into the ligand interaction of gold nanoparticles in aqueous environments and molecular interactions, which is key for understanding properties in real-world environments. These studies not only lay a foundation for incorporation of hybrid nanoparticles in sensing devices, but also provide insight for their use as stand-alone materials.
https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: TBD
Speaker: Dr. John DiTusa , Purdue University
Time: February 15, 2021 03:00 PM Eastern Time (US and Canada)
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Title: Incommensurate magnetism mediated by Weyl fermions in NdAlSi
Speaker: Dr. Jonathan Gaudet , NIST
Time: March 22, 2021 04:00 PM Eastern Time (US and Canada)
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Abstract: Emergent relativistic quasiparticles in Weyl semimetals are the source of exotic electronic properties such as surface Fermi arcs, the anomalous Hall effect, and negative magnetoresistance, all observed in real materials. Whereas these phenomena highlight the effect of Weyl fermions on the electronic transport properties, less is known about what collective phenomena they may support. In this talk, I will report a new Weyl semimetal, NdAlSi that offers an example. Using neutron diffraction, a long-wavelength magnetic order in NdAlSi whose periodicity is linked to the nesting vector between two topologically non-trivial Fermi pockets was observed, and characterized using density functional theory and quantum oscillation measurements. This work provides a rare example of Weyl fermions driving collective magnetism.
Bio:
Dr. Gaudet did his PhD under the supervision of Bruce Gaulin at McMaster University in Hamilton, Canada (2014-2018). There he studied neutron scattering of frustrated rare-earth pyrochlores. He then moved to do a postdoc with Collin Boholm at Johns Hopkins University (2018-2021) to study magnetic topological materials with neutrons. Very recently (March 1st), Dr. Gaudet moved to the NIST Center for Neutron Research in Gaithersburg, Maryland to start a position as Research scientist.
https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: MnBi2Te4.nBi2Te3: a happy marriage of magnetism and topology
Speaker: Dr. Ni Ni, UCLA
Time: April 5, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract: Magnetic topological material provides a great platform for discovering new topological states, such as the axion insulators, the Chern insulators, and the 3D quantum anomalous Hall (QAH) insulators. Recently, MnBi2Te4 was discovered to be the first material realization of an intrinsic antiferromagnetic topological insulator (TI) where the QAH effect was observed at a record high temperature in its two-dimensional limit. Since the interplay of the magnetism and band topology determines their topological natures, understanding and manipulating the magnetism inside magnetic TIs will be crucial. In this talk, I will present our discovery of two new magnetic topological materials MnBi2Te4.nBi2Te3 (n=1 and 3) which consist of alternating [MnBi2Te4] and n[Bi2Te3] layers [1, 2]. I will show that by reducing the interlayer magnetic coupling with the increasing number of spacer [Bi2Te3] layers, MnBi2Te4.nBi2Te3 can be tuned from Z2 antiferromagnetic TIs (n=0,1,2) to ferromagnetic axion insulators. Furthermore, I will show that a continuous fine control of the magnetism in MnBi4Te7 can be made by Sb doping where an AFM to FM switching emerges due to the formation of the Mn/Sb antisite disorders [3]. Our study provides a rare tunable material platform to investigate various emergent phenomena arising from the interplay of magnetism and band topology.
Bio:
My research focuses on the characterization of physical properties and structures of materials through thermodynamic, transport, X-ray and neutron measurements, with an emphasis on the design, synthesis and crystal growth of new materials. Our interests span a wide spectrum of materials, from intermetallics to oxides, especially superconductors and strongly correlated electron systems showing unusual electronic and magnetic ground states that can be perturbed by chemical doping, applied pressure or magnetic field. We aim at synthesizing new materials with nontrivial properties, characterizing quantum phases, and examining the different energy scales in solids. The interplay of magnetism, superconductivity and structure will be of particular interest.
https://gmu.zoom.us/j/96920316926?pwd=SjZybGp1N2c2QjBsWFVXcVpOMFc0dz09
Title: Use of Ultrafast Techniques in Studies of Charge Density Wave Systems
Speaker: Dr. Goran Karapetrov, Department of Materials Science and Engineering, Drexel University
Time: April 19, 2021 03:00 PM Eastern Time (US and Canada)
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Abstract: Studies of correlated electron systems are often focused on the complex interaction of charge, spin, orbital and lattice degrees of freedom. Ultrafast spectroscopies have been primary tools in experimental investigation of the dynamics of complex orders by exciting the system out of equilibrium using the pump pulse and applying variety of probes to see the response. The probing of the excited system can be achieved using optical, electronic and x-ray beams and different techniques provide pieces of the puzzle that one should carefully assemble. On the examples of few dichalcogenide CDW/superconducting materials such as NbSe2 and TiSe2 we will discuss the current understanding of the mechanism of the correlated electronic states and how this knowledge could be applied to more complex materials.
Bio:
Dr. Goran Karapetrov is a member of the faculty at the Department of Physics, Drexel University since 2011. Before joining Drexel, he was a staff member at the Materials Science Division at Argonne National Laboratory working on mesoscopic superconductivity and scanning tunneling microscopy and spectroscopy of superconductors. Dr Karapetrov obtained his diploma from the Department of Low Temperature Physics, Moscow State University, and PhD degree in Physics from Oregon State University.
Dr. Karapetrov’s research focuses on the physics of correlated electron systems such as charge density wave materials and superconductors. In his laboratory at Drexel, he uses both high spatial resolution probes (UHV STM, AFM) and high temporal resolution probes (ultrafast electron diffraction) to study local properties and dynamics of these systems.
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Panelists:
Dr. Patrick Vora, Director of QSEC & Associate Professor of Physics, GMU
Dr. Jacob Farinholt, Lead Quantum Scientist, Booz Allen Hamilton
Dr. Brandon Rodenburg, Physicist and Quantum Information Scientist, MITRE Corporation
Dr. Neil Zimmerman, Atom Scale Device Group Leader, NIST
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Quantum Week Event Information: https://qsec.gmu.edu/events/quantum-week/
Virtual Conference Hall of the Poster Session: https://gather.town/app/iYPdUV0zfX1sVNVx/QSEC%20Quantum%20Week
Speaker: Dr. Ilija Zeljkovic of Boston College
Abstract
The kagome lattice of transition metal atoms provides an exciting platform to study the interplay of electronic correlations and band topology. AV3Sb5 (A=K, Rb, Cs) is a recently discovered class of kagome metals that does not exhibitresolvable magnetic order, and yet, surprisingly, shows a large anomalous Hall response and superconductivity. In this talk, I will discuss our experiments on AV3Sb5 materials using low-temperature spectroscopic imaging scanning tunneling microscopy. In CsV3Sb5, we discover a cascade of different symmetry-broken electronic states as a function of temperature. At a temperature far above the superconducting transition Tc ~ 2.5 K, we reveal a tri-directional charge order with a 2a0 period that breaks the translation symmetry of the lattice. As the system is cooled down towards Tc, we observe an additional breaking of the six-fold rotation symmetry, which persists through the superconducting transition. This rotation symmetry breaking is observed as the emergence of an additional 4a0 unidirectional charge order and strongly anisotropic scattering attributed to the orbital-selective renormalization of the Vanadium kagome bands. I will conclude by discussing the symmetry of the 2a0 CDW state in KV3Sb5 and its response to an externally applied magnetic field. Our experiments reveal a complex landscape of electronic states that can co-exist on a kagome lattice, and provide intriguing parallels to high-Tc superconductors and twisted bilayer graphene.
Time
October 4, 2021, 03:00 – 04:00 PM Eastern Time (US and Canada)
Meeting Information:
Zoom
Meeting ID: 950 9309 9839
Passcode: 522625
https://gmu.zoom.us/j/95093099839?pwd=WnRhMU1hWlZFWGhLNHNaeDFZWU82UT09