Graduate Program in Spintronics Seminar“OPTICAL PROBE OF COHERENT PHENOMENAIN MULTI-FUNCTIONAL MATERIALS”

Giti KHODAPARAST

Professor.

VIRGINIA POLYTECHNIC INSTITUTE & STATE
UNIVERSITY: DEPARTMENT OF PHYSICSTime : 2:00pm-4:00pm
Date : Friday,

January 11, 2019

Venue: Seminar Room 2 :407
Education and Research Building,Materials Science and Materials Processing,
Graduate School of Engineering

Contact to : Makoto Kohda(makoto@material.tohoku.ac.jp)

Optical Probe of Coherent Phenomena in Multi-Functional Materials
Giti Khodaparast, Physics Department, Virginia Tech, Email: khoda@vt.edu
Intense laser pulses can generate carriers, spins, phonons, and magnons far from equilibrium
states. Information about the dynamical behavior of these nonequilibrium states can be elucidated by: 1)
the electronic structure, 2) carrier scattering and relaxation mechanisms, including carrier-phonon andcarrier-carrier scattering, 3) spin and magnetization dynamics, and 4) dynamical many-body interactions.
For example, coherent acoustic phonons which are ultrasonic strain pulses can result in a broad optical
spectrum from GHz up to THz 1,2,3,4 The possibility of manipulating Coherent Phonons (CP) could leadto develop new techniques such acoustic imaging as well as better understanding and control of electronic
and optical properties in devices. Exploring the interaction of CP with carriers, magnetic impurities, andphotons can open new prospective of phononics on nanoscale. For example, the manipulation of spins insemiconductors without the application of magnetic fields opens the door to the next generation of devices,where the electronic computation and magnetic memory can be performed on the same chip. In this talk,I will present several time resolved studies including CP generation and control in multifunctional
materials such as ferromagnetic semiconductors and mutliferroics 1,5.
B. A. Magill, K-D Park, Y. Zhou, A. Chopra, Maurya, S. Priya, M. B. Raschke, A. Belyanin, C. J.
Stanton, G. A. Khodaparast ,“Ultrafast Anisotropic Optical Response and Coherent Acoustic Phonon
Generation in Polycrystalline BaTiO3-BiFeO3”, Energy Harvesting and Systems. Volume 3, Issue 3, 229,April (2016).
2M. P. Hasselbeck, D. Stalnaker, L. Schlie, A. Stintz, and T. J. Rotter, “Fress space radiation of coherent,coupled plasmon-phonon modes from InAs,” Physica B 314, 158 (2002).
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M. P. Hasselbeck, D. Stalnaker, L. Schlie, A. Stintz, T. J. Rotter, and M. Sheik-Bahae, “Emission ofterahertz radiation from coupled plasmon-phonon modes in InAs,” Phys. Rev. B 65, 233203 (2002).
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C. K. Sun, J. C. Liang, C. J. Stanton, A. Abare, L. Coldren, and S. P. DenBars, “Large coherent acousticphonon oscillation observed in InGaN/GaN multiple-quantum wells,” Appl. Phys. Lett. 75, 1249 (1999).
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B. Madon, H. Byul Kang, M. Gyu Kang, D. Maurya, B. Magill, M. Alves, J.-E. Wegrowe, H.-J. Drouhin,S. Priya, and G. A. khodaparast, “Room Temperature Ferromagnetic Resonance in Hetero-Epitaxial BTOBFO/LSMO Magnetoelectric Composite”, AIP Advances 8 (10), 105034 (2018). Editor’s Pick.
Short Bio:
Professor Giti Khodaparast research activities at Virginia Tech have been focused to utilize and enhance
the importance and power of magneto-optical spectroscopy to explore quantum coherence, correlations,and many-body effects in several materials systems that can play important roles in developing concepts
for the next generation of devices or shed lights on the underlying interactions at the nanoscale. She has
established modern experimental techniques including femtosecond time resolved optical, magnetooptical, and nonlinear spectroscopy at the physics department. In addition, she has established strong
national and international collaborations with large research facilities including the National High
Magnetic Field Laboratory in Florida, and the Megagauss Laboratory in Kashiwa, Japan. She is therecipient of both the NSF career and the AFOSR young investigator awards.
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