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Mon Jan 15, 2018

Physics Colloquium: Dr. Rebecca Milot, Oxford University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Optoelectronics of Hybrid Metal Halide Perovskites for Photovoltaics

Dr. Rebecca Milot
Oxford University

This lecture has been generously funded through The IBM Corporate Lecture Series, created to foster women's inclusion in science, technology, engineering and mathematics (STEM).

 

Hybrid metal halide perovskites have shown extraordinary success as active layers in solar cells, with power conversion efficiencies rivalling existing silicon technologies. A benefit of perovskites is that they are comprised of low-cost, earth abundant materials, and perovskite thin films are easily synthesized with simple starting materials. Additionally, they exhibit exceptional optoelectronic properties, which include strong absorption across the entire visible spectrum, long charge-carrier lifetimes, and high charge-carrier mobilities. Optical-pump/THz-probe (OPTP) spectroscopy has proven to be an essential technique for studying the charge-carrier dynamics and charge-carrier mobility in many of these materials including lead-based, tin-based, two-dimensional, and mixed-halide/mixed-cation perovskites. These studies have determined that the charge-carrier mobility and charge-carrier recombination dynamics are strongly dependent on chemical composition, defect density, band structure, and crystallinity.

Posted In: Colloquia

Wed Jan 17, 2018

Physics Colloquium: Dr. Fahad Mahmood, Johns Hopkins University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Illuminating and manipulating quantum materials with femtosecond light

Dr. Fahad Mahmood
Johns Hopkins University

Uncovering and controlling emergent phenomena in quantum materials through external stimuli is a central goal of modern condensed matter physics. However, a major challenge lies in disentangling many different yet closely coupled interactions and fluctuating orders. Moreover, since many quantum processes in these materials are coherent only over ultrashort time scales, it is difficult to probe them using conventional static techniques. In this talk, I will demonstrate how ultrafast femtosecond optical techniques can selectively decipher and alter collective behavior in two of the most intensely researched quantum materials in the past decade, high-Tc superconducting cuprates and topological insulators. For superconducting cuprates, ultrafast infra-red pump-probe and time-domain THz spectroscopy are used to detect elementary excitations and short-lived fluctuating orders. For topological insulators, time-and-angle resolved photoemission spectroscopy is used to dynamically engineer new light-induced ‘Floquet-Bloch’ electronic states. Such studies lay the foundation for utilizing coherent light-matter interaction to steer materials into a desired quantum phase.

Posted In: Colloquia

Mon Jan 22, 2018

Nuclear Physics Seminar: Prof. Elias Garratt

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Understanding and controlling material properties through focused ion beam technology

Prof. Elias Garratt
Michigan State University

Hosted by Prof. Simon

Posted In: Nuclear Seminar

Tue Jan 23, 2018

Our Universe Revealed: Dr. Jason Kalirai, Multi-Mission Project Scientist, Space Telescope Science Institute

7:30 PM - 8:30 PM
101 Jordan Hall of Science

Hubble’s Recent Hits and a Look Forward to the James Webb Space Telescope

Dr. Jason Kalirai, Multi-Mission Project Scientist, Space Telescope Science Institute

Part of the Our Universe Revealed Lecture Series

Posted In: Special Lectures and Events

Wed Jan 24, 2018

Physics Colloquium: Dr. Jason Kalirai, STScI

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Seeing Galaxies as Collections of Stars

Dr. Jason Kalirai
STScI

Since the pioneering work of Henry Norris Russell 100 years ago, the study of nearby stellar populations in the Milky Way has served as a foundation for our quest to understand the nature of galaxies in the Universe. Today, studies of resolved stellar populations constrain fundamental relations that define how stars form, how they evolve over time, and how they dramatically transform themselves in the final stages of stellar death.  Understanding these processes give us a prescription to interpret all light from the Universe and to measure the physical state of galaxies. In this talk, I'll present new highest-precision observations that we've taken of nearby stellar populations, using the biggest ground and space based telescopes such as the Keck 10-meter telescope on Mauna Kea and the Hubble Space Telescope in orbit. These data are providing unprecedented constraints on our understanding of how stars evolve, and act as a bridge between studies of the nearby and distant Universe. I'll also discuss new opportunities for stellar population studies with an impressive suite of astronomical tools that are now on our horizon - GAIA, JWST, LSST, WFIRST, 30-meter telescopes.

Posted In: Colloquia

Thu Jan 25, 2018

Physics Colloquium: Dr. Chunhui Du, Harvard University

4:00 PM - 5:00 PM
123 Nieuwland Science Hall

Control and local measurements of the spin chemical potential in a magnetic insulator

Dr. Chunhui Du
Postdoctoral Fellow, Department of Physics, Harvard University

This lecture has been generously funded through The IBM Corporate Lecture Series, created to foster women's inclusion in science, technology, engineering and mathematics (STEM).

In recent decades, a large scientific effort has focused on harnessing spin transport for providing insights into novel materials and low-dissipation information processing. We introduce single spin magnetometry based on nitrogen-vacancy (NV) centers in diamond as a new and generic platform to locally probe spin chemical potentials which essentially determine the flow of spin currents. We use this platform to investigate magnons in a magnetic insulator yttrium iron garnet (YIG) on a 100 nanometer length scale. We demonstrate that the local magnon chemical potential can be systematically controlled through both ferromagnetic resonance and electrical spin excitation, which agrees well with the theoretical analysis of the underlying multi-magnon processes. Our results open up new possibilities for nanoscale imaging and manipulation of spin-related phenomena in condensed-matter systems.

Posted In: Colloquia

Mon Jan 29, 2018

Nuclear Physics Seminar: Dr. Sophia Han

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Sophia Han
University of Tennessee Knoxville

Hosted by Prof. Surman
 …

Posted In: Nuclear Seminar

Tue Jan 30, 2018

Astrophysics Seminar: Mr. Steven Villanueva, OSU

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

A Year with the DEdicated MONitor of EXotransits and Transients (DEMONEXT), an Automated and Robotic Telescope for Exoplanet and Transient Follow Up

Mr. Steven Villanueva
The Ohio State University

DEMONEXT is a 0.5-m robotic telescope that has been in operation since May 2016. Fully automated, DEMONEXT has observed over 200 transits of exoplanet candidates for the KELT survey, including confirmation observations of KELT-20b. DEMONEXT achieves 2-4 mmag precision with unbinned, 20-120 second exposures, on targets orbiting V<13 host stars. Millimagnitude precision can be achieved by binning the transits on 5-6 minute timescales. During observations of 8 hours with hundreds of consecutive exposures, DEMONEXT maintains sub-pixel (<0.5 pixels) target position stability on the CCD during good observing conditions, with degraded performance during poor observing conditions (<1 pixel). DEMONEXT achieves 1% photometry on targets with V<17 in 5 minute exposures, with detection limits of V~21. In addition to the 150 transits observed by DEMONEXT, 50 supernovae and transients haven been observed for the ASAS-SN supernovae group, as well as time-series observations of Galactic microlensing, active galactic nuclei, stellar variability, and stellar rotation.

Posted In: Astrophysics Seminar

Mon Feb 5, 2018

Nuclear Physics Seminar: Mr. Cory Thornsberry

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Mr. Cory Thornsberry
University of Tennessee Knoxville

Hosted by Prof. Ahn

Posted In: Nuclear Seminar

Tue Feb 6, 2018

Astrophysics Seminar: Dr. Claudia Scarlata, University of Minnesota

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Dr. Claudia Scarlata
University of Minnesota

Hosted by Prof. Howk

Posted In: Astrophysics Seminar

Wed Feb 7, 2018

Physics Colloquium: Dr. Long Ju, Cornell University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Long Ju
Kavli Fellow
Kavli Institute of Nano Science
Cornell University…

Posted In: Colloquia

Mon Feb 12, 2018

Nuclear Physics Seminar: Dr. Brian Bucher

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Brian Bucher
(ND PhD)
Idaho National Laboratory

Hosted by Prof. Aprahamian

Posted In: Nuclear Seminar

Tue Feb 13, 2018

Astrophysics Seminar: Mr. Jared Coughlin

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Mr. Jared Coughlin
Graduate Student, University of Notre Dame

Hosted by Prof. Mathews

Posted In: Astrophysics Seminar

Wed Feb 14, 2018

Physics Colloquium: Dr. Emrah Turgut, Cornell University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Spin dynamics of topological spin textures in chiral magnets

Dr. Emrah Turgut
Postdoctoral Associate, Applied and Engineering Physics
Cornell University

The chiral spin textures are a consequence of the anti-symmetric exchange interaction, which presents in the material systems with broken inversion symmetry, such as B20 FeGe. This interaction enables chiral magnetic order, including topologically non-trivial magnetic skyrmions, which display rich new magnetic phenomena and require low critical current densities to manipulate.  This makes magnetic skyrmions a promising platform for power-efficient spintronics applications. Therefore, a deeper understanding of the static and dynamic magnetic properties of these materials will be a key step toward their application in spintronic devices. In this talk, I will present our study of both sputtered, epitaxial B20 FeGe and B20 FeGe grown using vapor transport. In particular, I will discuss microwave absorption spectroscopy (MAS) of bulk, single crystal FeGe with which we identify the spin dynamics of all magnetic phases. These results reveal the critical role of substrate-induced strain on the magnetic phases of B20 FeGe.  To gain better control over strain and to tune the strength of anti-symmetric exchange, I grew B20 FeGe and MnxFe1-xGe on Si with MBE. After characterization using electron and X-ray diffraction, magnetometry, and cryo-Lorentz-STEM imaging, we study MAS of these films. We identify a new spin wave mode along the film thickness, with a wavelength that matches its helical period, enabling a new, simple method of quantitatively characterizing the anti-symmetric exchange.

Posted In: Colloquia

Mon Feb 19, 2018

Nuclear Physics Seminar: Dr. Rodney Orford

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Rodney Orford
Argonne National Laboratory

Hosted by Prof. Aprahamian

Posted In: Nuclear Seminar

Wed Feb 21, 2018

Physics Colloquium: Dr. Yingjie Zhang, University of Illinois at Urbana-Champaign

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Yingjie Zhang
Beckman Postdoctoral Fellow
Department of Physics
University of Illinois at Urbana-Champaign…

Posted In: Colloquia

Mon Feb 26, 2018

Nuclear Physics Seminar: Dr. Mark Roberts

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Mark Roberts
Woods Hole Oceanographic Institution

Hosted by Prof. Peaslee

Posted In: Nuclear Seminar

Tue Feb 27, 2018

Astrophysics Seminar: Dr. Gen Chiaki

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Dr. Gen Chiaki
Georgia Tech

Hosted by Prof. Beers

Posted In: Astrophysics Seminar

Wed Feb 28, 2018

Physics Colloquium: Dr. Yang Liu, Stanford University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Yang Liu
GLAM Postdoctoral Research Fellow
Stanford University…

Posted In: Colloquia

Mon Mar 5, 2018

Nuclear Physics Seminar: Prof. Partha Chowdhury

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Prof. Partha Chowdhury
University of Massachusetts Lowell

Hosted by Prof. Garg

Posted In: Nuclear Seminar

Tue Mar 6, 2018

Astrophysics Seminar: Dr. MacKenzie Warren, MSU

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Dr. MacKenzie Warren
(ND PhD)
MSU

Hosted by Prof. Mathews

Posted In: Astrophysics Seminar

Mon Mar 19, 2018

Nuclear Physics Seminar: Dr. Amy Roberts

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Amy Roberts
(ND PhD)
University of Colorado Denver

Hosted by Dr. deBoer

Posted In: Nuclear Seminar

Tue Mar 20, 2018

Astrophysics Seminar: Prof. Robert Scherrer, Vanderbilt University

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

The cosmological Lithium Problem

Prof. Robert Scherrer
Vanderbilt University

Hosted by Prof. Mathews

Posted In: Astrophysics Seminar

Wed Mar 21, 2018

Physics Colloquium: Prof. Robert Scherrer, Vanderbilt University

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Science and science fiction

Prof. Robert Scherrer
Chair, Department of Physics and Astronomy
Vanderbilt University

Hosted by Prof. Mathews

Posted In: Colloquia

Mon Mar 26, 2018

Nuclear Physics Seminar: Dr. Jie Chen

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Dr. Jie Chen
Argonne National Laboratory

Hosted by Prof. Caprio

Posted In: Nuclear Seminar

Tue Mar 27, 2018

Astrophysics Seminar: Ms. Xilu Wang

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Ms. Xilu Wang
Graduate Student
University of Illinois Urbana-Champaign

Hosted by Prof. Surman

Posted In: Astrophysics Seminar

Wed Mar 28, 2018

Physics Colloquium: Dr. Bernard Rauscher, Goddard Space Flight Center

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Dr. Bernard Rauscher
Goddard Space Flight Center

Hosted by Prof. Crepp

Posted In: Colloquia

Wed Apr 4, 2018

Physics Colloquium: Prof. Jing Xia, University of California, Irvine

4:00 PM - 5:00 PM
118 Nieuwland Science Hall

Title TBA

Prof. Jing Xia
Department of Physics and Astronomy
University of California, Irvine…

Posted In: Colloquia

Mon Apr 9, 2018

Nuclear Physics Seminar: Ms. Gwen Gilardy

4:00 PM - 5:00 PM
124 Nieuwland Science Hall

Title TBA

Ms. Gwen Gilardy
University of Notre Dame

Hosted by Prof. Couder

Posted In: Nuclear Seminar

Tue Apr 10, 2018

Astrophysics Seminar: Dr. Brendan Bowler, University of Texas

12:30 PM - 1:30 PM
184 Nieuwland Science Hall

Title TBA

Dr. Brendan Bowler
University of Texas

Hosted by Prof. Crepp

Posted In: Astrophysics Seminar

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