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The MagLab is funded by the National Science Foundation and the State of Florida.

Condensed Matter Seminars

The MagLab’s Condensed Matter Science Group hosts regular seminars featuring the work of visiting scientists. All seminars are open to the public and take place in Room B101 of the MagLab.


Date: February 9, 2024

Speaker: Hari Srikanth, University of South Florida

Title: The rise of chatbots and tips on writing manuscripts – An Editor’s Perspective

Host: Laura Greene

Location: MagLab B 101 at 3:00 PM-4:00 PM

Abstract: This talk will introduce good practices from a journal editor’s perspective as well as an active senior researcher’s point of view in writing up your research results for peer-reviewed publications in recognized journals, especially in condensed matter and materials physics. In recent times there has been a paradigm shift in the way large volume of data is handled through AI, machine learning which has led to the emerging popularity of chatbots such as OpenAI’s ChatGPT, Microsoft’s Bing and Google’s Bard. There are benefits in using chatbots to help improve and polish written drafts but there are also the risks of incorrect logic, questions on scientific ethics and loss of creativity and originality. I will present some specific examples to illustrate the advantages and disadvantages of using chatbots in scientific publishing. A general view on all this will be presented in a 45 min perspective talk followed by interactive Q&A and discussion with the attendees.

Bio: Hari Srikanth is a Distinguished University Professor at the University of South Florida. He received his Ph.D. in experimental condensed matter physics from the Indian Institute of Science, Bangalore and has been at USF since 2000 where he directs the Functional Materials Laboratory. His research spans a wide range of topics in magnetism and magnetic materials. He has over 300 publications and has given over 200 invited talks around the world. In 2019, he was an IEEE Magnetics Society Distinguished Lecturer. Hari is a Fellow of the American Physical Society, Fellow of the Institute of Physics and a Senior Member of IEEE. Hari also has over a decade of experience as an Editor for several condensed matter and materials physics journals. He was an Associate Editor for Journal of Applied Physics from 2014-2020. At present he serves as an Associate Editor for Physical Review B and as an Editor for Journal of Alloys and Compounds. He is also an Editorial Board Member for Journal of Magnetism and Magnetic Materials.


Date: October 27, 2023

Speaker: Milan Orlita, Laboratoire National des Champs Magnétiques Intenses, CNRS, Grenoble, France

Title: Magneto-optics of van-der-Waals antiferromagnets

Host: Mykhaylo Ozerov

Location: MagLab B 101 at 3:00 PM-4:00 PM

Abstract: Infrared and THz magneto-spectroscopy serves as a relevant tool for investigating a wide range of low-energy excitations in solids. During my presentation, I will provide a succinct overview of research activities employing this experimental technique combined with the high-magnetic-field facility at the LNCMI in Grenoble. My talk will be primarily focused on recent results obtained on layered antiferromagnets, particularly those belonging to the FePS3 family. These investigations have revealed a surprisingly complex magneto-optical response which goes beyond the conventional picture of classical antiferromagnetic resonance. We interpret it in terms of magnon-polarons and magnon excitations with high angular momenta.

Date: August 24, 2023

Speaker: Rong Cong, Brown University and Center for Intergrated Nanotechnology (CINT)

Title: Orbital glass induced unconventional magnetic order in a correlated insulator

Host: Arneil Reyes

Location: MagLab B 101 at 11:00 AM-12:00 PM

Abstract: Intertwined electronic and orbital degrees of freedom in strongly correlated materials with strong spin-orbit-coupling has shown to give rise to many exotic quantum phenomena, especially to emergent quantum phases and transitions [1]. Coupling between the spin and orbit degrees of freedom can lead to two different viable order parameters: magnetic (spin) order and multi-polar (orbital) order. In this talk, I will present our recent direct observation of an orbital glass state caused by such a coupling in the 5d1 relativistic Mott insulator Ba2NaOsO6 by implementing a technique that is able to independently probe interactions of different symmetries [2]. I will talk about simultaneous measurements of the fluctuations in the spin and orbital order using a Hahn echo sequence, giving an unprecedented view into the nature of a complex spin-orbit phase transition. We observe short-range quadrupolar order up to room temperature and a dramatic increase of orbital fluctuations near the phase transition. The presence of quadrupolar fluctuations well above the phase transition solves a long-standing puzzle of missing entropy in this material. In the end of the talk, I will transition the focus and discuss our most recent progress in using resistive detected magnetic resonance techniques to probe spin properties in 2D quantum materials and phases.

[1] Witczak-Krempa, William, et al. "Correlated quantum phenomena in the strong spin-orbit regime." Annu. Rev. Condens. Matter Phys. 5.1 (2014): 57-82.

[2] Carr, Stephen, et al. "Multi-modal spectroscopy of phase transitions." Phys. Rev. B 108, 054421 (2023)

Date: August 22, 2023

Speaker: Shengzhi Zhang, National MagLab, Los Alamos National Laboratory

Title: Electronic and magnetic phase diagrams of quantum spin liquid candidates under high magnetic fields

Host: Arneil Reyes

Location: MagLab B 101 at 11:00 AM-12:00 PM

Abstract: One crucial step toward understanding a compound is establishing its phase diagram via parameter tuning, such as temperature (T) and magnetic field (H). By examining these phase diagrams, we gain valuable insights into the underlying physics behind the phases. Additionally, examining the intrinsic spin dynamics is indispensable to further achieve a microscopic understanding of the compound's behaviors within each phase. In this talk, I will present our recent work on constructing comprehensive T-H phase diagrams of a potential Kiatev quantum spin liquid candidate, Na2Co2TeO6. Using five different techniques including magnetization, specific heat, dielectric constant, magnetostriction, and magnetocaloric effect measurements, I have identified four distinct phases, among which one exhibits the characteristics of a potential field-induced quantum spin liquid phase. Moreover, I successfully resolved a long-standing debate concerning the magnetic structure (zigzag vs. triple-Q) for the low-field phase utilizing a symmetry-sensitive electric polarization measurement. In the end, I will propose a couple of quantum spin liquid candidates where nuclear magnetic resonance measurement will play an important role in identifying the nature of their high-field phases.

Date: August 11, 2023

Speaker: Raquel D. Ribeiro, Iowa State University

Title: La2Ni7 – A Small Moment System with AFM Order

Host: Greg S Boebinger

Location: MagLab B 101 at 3:00 PM-4:00 PM

Abstract: Small moment magnetic systems attract attention as their magnetic ordering temperatures can often be tuned towards a quantum phase transition, using non-thermal parameters, to study exotic physical phenomena such as unconventional superconductivity, heavy Fermi liquid, etc. La2Ni7 presents a series of AFM phase transitions at 61.0K, 56.5K, and 42.2K with a low saturated moment of 0.12μB/Ni. I will highlight the main results of recent collaborative works in La2Ni7 single crystal. Analysis of M(T), M(H), ρ(T) and ρ(H) data allow for the construction of anisotropic H-T phase diagrams. Neutron diffraction studies have found the propagation vectors and magnetic moment directions of the three magnetically ordered phases. ARPES data reveal several electron and hole pockets that have hexagonal symmetry. NMR also shed light onto the nature of the magnetic order and how it impacts the bandstructure. DFT calculations show reasonable agreement experimental data, demonstrating their applicability to itinerant antiferromagnet systems.

Date: August 10, 2023

Speaker: Xiaoling (Cocoa) Wang, California State University East Bay

Title: Untangling the unconventional coupling between charge density wave order and superconductivity in kagome superconductors

Host: Arneil Reyes, CMS - DC Field

Location: MagLab B 101 at 11:00 AM-12:00 PM

Abstract: The investigation of the interplay between superconductivity and other ordered states, such as charge density wave (CDW) state, constitutes a fundamental aspect of condensed matter physics. The discovery of the layered kagome metal AV3Sb5 (A=K, Rb, Cs) offers a new experimental platform for exploring this competition.

AV3Sb5 lattices exhibit both a non-conventional CDW order (TCDW ∼ 80 − 104 K) and a topological superconducting ground state (TC ∼ 0.9 − 2.5 K). In this talk, I will present our investigation on the superstructure deformation in the crystal lattice associated with the CDW order, utilizing Nuclear Magnetic Resonance (NMR) spectroscopy. Our observations shed light on the formation and configuration of CDW states and indicate a new avenue for further exploring the electronic structure evolution of various instabilities of kagome superconductors.

Date: April 21, 2023

Speaker: Long Ju, MIT

Title: Electron correlation and topology in rhombohedral multilayer graphene

Host: Cyprian Lewandowski

Location: MagLab B 101 at 3:00 PM-4:00 PM

Abstract: Rhombohedral stacked multilayer graphene is an ideal platform to search for correlated electron phenomena, due to its pair of flat bands touching at zero energy and further tunability by an electric field. Furthermore, its valley-dependent Berry phase at zero energy points to possible topological states when the isospin symmetry is broken by electron correlation. In this talk, I will first show our efforts on the optical spectroscopy study of trilayer graphene/hBN moire superlattice. We observed optical signatures of flat moire band formation and Mott insulator due to band splitting at half-filling. Then I will talk about DC transport measurements of pentalayer graphene without any moire superlattices. We observed a plethora of correlated and topological states including a ferro-valleytronic half-metal, a correlated insulating state and Chern insulator states. Our results point to a new direction of exploring electron correlation and topology in natural 2D crystals where the layer number plays a critical role.

Date: March 3, 2023

Speaker: Jerome K. Hyun, Department of Chemistry and Nanoscience, Ewha Womans University, Korea

Title: Modulating light scattering and absorption for active structural colors

Host: Hanwei Gao (Physics)

Location: MagLab B 101 at 2:30 PM-4:30 PM

Abstract: Structural colors refer to colors arising from the scattering and interference of light by judiciously designed nanostructures. To be viable candidates for display or smart colorimetric sensing applications, their responses must be dynamic. To this end, our lab has worked on designs that can be tuned through a suite of external stimuli including electricity, humidity, and chemical vapor. Unlike plasmonic designs that require the excitation of surface plasmons, our approach mainly relies on photonic responses such as Mie resonances and dielectric waveguide-array modes which free our system from ohmic damping and the interdependence between wavelength and intensity. We also extend our approach to the microwave regime where unprecedentedly thin electromagnetic wave absorbers are realized.

Date: February 17, 2023

Speaker: Sergio de la Barrera, Massachusetts Institute of Technology

Title: Superconductivity in an engineered moiré quasiperiodic system

Host: Cyprian Lewandowski

Location: MagLab B 101 at 3:00 PM-4:00 PM

Abstract: View abstract

Date: February 3, 2023

Speaker: Pavan Hosur, University of Houston

Title: Superconductor vortices in Weyl semimetals

Host: Hitesh Changlani

Location: MagLab B 101 at 3:00 PM-4:30 PM

Abstract: View abstract

Last modified on 23 August 2023