Past Events
| Event | Date | Summary |
| Matthew Gilbert (UIUC) | Mon. April 26th, 2021 12:45 pm-1:45 pm |
Elucidating the Effects of Magnetism in Topological Materials Matthew J. Gilbert Department of Electrical and Computer Engineering & Department of Physics, University of Illinois, Urbana, IL Abstract.– For many years, topological materials have been the subject of great interest from condensed matter experimentalists and theorists. While there is a continued push to predict and measure new topological phenomena there exists a large class of “well-known” topological materials, or those that have been thoroughly characterized for their basic topological properties, that may serve as a testbed for new physics and applications by utilizing the inherent properties of these topological materials. |
| Charles Brown (University of California, Berkeley) | Mon. April 12th, 2021 12:45 pm-1:45 pm |
Title: Non-equilibrium phenomena of ultracold quantum gasses trapped in optical lattice potentials. Charles Brown, Department of Physics, University of California, Berkeley Abstract: Experiments with quantum gasses trapped in optical lattices, an analog of particles in a solid crystalline lattice, shed light on the behavior of condensed-matter systems, including solid-state materials. Studying non-equilibrium phenomena of quantum gasses in optical lattices provides a method to explore how a lattice’s energy band structure is augmented by inter-particle interactions (band renormalization). Separately, studying such phenomena provides a method to explore the geometric and topological structure of a lattice’s energy bands. Continue reading… Charles Brown (University of California, Berkeley) |
| Alessandro Principi (University of Manchester) | Mon. April 5th, 2021 12:45 pm-1:45 pm |
Title: Thermal transport in clean semimetals – an application of electron hydrodynamics Alessandro Principi, Department of Physics & Astronomy, University of Manchester Abstract: It is well known that clean compensated semimetals, e.g. two-dimensional monolayer and bilayer graphene near the charge neutrality point, can exhibit a greatly enhanced Lorenz ratio between the electronic thermal conductivity and the electric conductivity. In contrast to this, three-dimensional compensated semimetals such as WP2 and Sb with indirect negative gap typically exhibit a reduced Lorenz ratio. We propose that the reason for this puzzling difference lies in the ability of indirect-gap semimetals to sustain sizable regions of electron-hole accumulation near the contacts, Continue reading… Alessandro Principi (University of Manchester) |
| Christopher Gutierrez (UCLA) | Mon. March 29th, 2021 12:45 pm-1:45 pm |
Global density wave formation in graphene via local symmetry breaking Abstract.– Two-dimensional materials offer a robust platform for investigating emergent behavior owing to the high tunability of their electronic properties. For instance, the ability to design electronic band structures through moiré superlattices in twisted graphene multilayers has led to the discovery of several symmetry-broken and topological phases. However, such twisted structures require exquisite care in their assembly and have micrometer dimensions that make spectroscopic measurements challenging. In this talk, I will describe an alternative method to induce a symmetry-broken phase in graphene at the millimeter scale. |
| Santosh Kumar | Mon. March 22nd, 2021 12:45 pm-1:45 pm |
Topological phase transitions of p-orbitals (Group-V) in 2D honeycomb lattices Topological materials, which hold promise for a wide range of technological applications due to their exotic electronic properties, have attracted a great deal of theoretical and experimental interest over the past decade, culminating in the 2016 Nobel Prize in physics. In this talk, I will explore the universal topological properties of p-orbitals placed in 2 dimensional D6h symmetry which is realized in real materials made of 2D group V-elements (Sb, |
| No seminar (March Meeting) | Mon. March 15th, 2021 12:45 pm-1:45 pm |
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| Andrew Lucas (University of Colorado Boulder) | Mon. March 8th, 2021 12:45 pm-1:45 pm |
Viscous fluids of electrons Department of Physics, University of Colorado Boulder Abstract.– It was conjectured over 50 years ago that electrons in high-quality conductor could flow collectively as a viscous fluid, just like air or water. While impurities and Umklapp scattering forbid this behavior in conventional metals, it has now become possible to study electrons that flow like classical fluids in high-quality devices. I will overview the nature of hydrodynamic transport in electrons together with some recent experiments that allow us to directly probe this behavior. Continue reading… Andrew Lucas (University of Colorado Boulder) |
| Ivar Martin (Argonne National Laboratory) | Mon. March 1st, 2021 12:45 pm-1:45 pm |
Exciting dynamics in multiple time dimensions Ivar Martin, Materials Science Division, Argonne National Laboratory Abstract. — Externally driving a dynamical system, be it quantum or classical, effectively increases the number of its time dimensions. In this talk, I will describe how the extra time dimensions can be harnessed to synthesize topological insulators purely in the time domain, describe their possible applications for energy conversion and quantum engineering, and point out connections to localization and chaos.
Host: Shulei Zhang |
| Luqiao Liu (MIT) | Mon. February 22nd, 2021 12:45 pm-1:45 pm |
Modulating magnon transport in ferromagnetic and antiferromagnetic materials Luqiao Liu, Electrical Engineering and Computer Science, MIT Abstract.– Spin waves are considered as one of the promising candidates for realizing unconventional computing and information processing. Compared with other forms of waves, spin wave has the advantage of short wavelength, intrinsic nonlinearity, and non-reciprocity. In this talk, I will discuss some of our experimental efforts on developing magnonic structures for these purposes. In the first effort, we demonstrated mutual interactions between magnons and magnetic domain walls in a ferromagnetic thin film, |
| Carla Verdi (University of Vienna) | Mon. February 15th, 2021 12:45 pm-1:45 pm |
First-principles calculations of polarons in real materials Carla Verdi, Faculty of Physics, University of Vienna Abstract. — Polarons are quasiparticles formed by electrons ‘dressed’ by a phonon cloud and represent a paradigmatic example of an emergent state in condensed matter. The presence of polarons can strongly influence the fundamental characteristics and functionalities of the host materials. Despite the broad scientific and technological interest in polarons, their properties are poorly understood. In this talk, I will present our recent work aimed at describing polarons from first principles in real materials. |
| Sayak Dasgupta (University of British Columbia) | Mon. February 8th, 2021 12:45 pm-1:45 pm |
Field theories of micromagnetism in XY ferromagnet and antiferromagnet Sayak Dasgupta Stewart Blusson Quantum Matter Institute, University of British Columbia Abstract. — Micromagnetic field theories effectively capture the long-range static structures and dynamics of ordered spin systems at temperatures below their ordering temperatures. The field theory, if expressed in the correct form, further elucidates hidden features in the order. We discuss two such instances. First, we take a look at the 2+1D XY ferromagnet whose continuum field theory has been extensively studied in the context of the Kosterlitz-Thouless phase transition [1]. Continue reading… Sayak Dasgupta (University of British Columbia) |
| Mesfin Tsige (University of Akron) | Mon. February 1st, 2021 12:45 pm-1:45 pm |
Spreading Dynamics of Water Droplets on a Completely Wetting Surface Mesfin Tsige School of Polymer Science and Polymer Engineering, The University of Akron Abstract. — There is a tremendous need for a greater understanding of the properties of matter at surfaces and interfaces at the nanometer scale mainly driven by the unprecedented impact of nanoscale materials in current industrial products. It is well known that matter behaves in complex ways and exhibits exotic properties at nanometer length scales. However, understanding the behavior of matter at such length scales using experimental methods has in general been very difficult. |