Texas Tech University

Ioannis Chatzakis, Ph.D.

Assistant Professor
Department of Physics and Astronomy

Email: ioannis.chatzakis@ttu.edu

Phone: +1 (806) 834-5414

Texas Tech University
Department of Physics & Astronomy
Box 14051, Lubbock, TX 79409-1051 

Science Building 116

Photo Description

Research Interests

My research focuses on the optical and electronic properties of nanomaterials and nanostructures, and in particular, on understanding the fundamental processes related to the dynamics of charge carriers, phonons, and other excitations (i.e. polaritons). Understanding the principles that govern these excitations will enable the fabrication of optoelectronic and photonic devices with novel and enhanced functionalities. I also develop new methods for THz generation/modulation by artificial nanostructures, and investigate novel methods for light confinement beyond the diffraction limit. In addition, I study materials that operate as single photon sources (quantum light emitters) for applications in quantum information systems. I use femtosecond pump-probe techniques complemented by other optical spectroscopy methods.


Ph.D., Physics, Kansas State University 2009
M.Sc., Physical Chemistry, Applied Molecular Spectroscopy 2004
B.Sc., Electrical Engineering, Hellenic Mediterranean University 1996

Awards and Fellowships

Postdoctoral fellow of the American Society of Engineering Education (ASEE) residing in U.S. Naval Research Laboratory (Washington, DC; 2016-2019)

Selected Publications

[1] I. Chatzakis, R. B. Davidson II, A. D. Dunkelberger, J. Freitas, A. Giles, C. T. Ellis, J. G. Tischler, J. D. Caldwell, and J. C. Owrutsky, ``Rapid Bimolecular and Defect-Assisted Carrier Recombination in Hexagonal Boron Nitride ", American Chemical Society J. Phys. Chem. C 123, 14689 (2019)

[2] D. C. Ratchford, C. Winta, I. Chatzakis, C. T. Ellis, N. Passler, J. Winterstein, P. Dev, I. Razdolski, J. G. Tischler, I. Vurgaftman, M. Katz, N. Nepal, M. T. Hardy, J. A. Hachtel, J. C. Idrobo, T. Reinecke, A. J. Giles, D. S. Katzer, N. D. Bassim, R. Stroud, M. Wolf, A. Paarmann, and J. D. Caldwell ``Controlling the Infrared Dielectric Function through Atomic-Scale Heterostructures ", American Chemical Society Nano, 13, 6730 (2019)

[3] I. Chatzakis, A. Krishna, J. Gilberstone, A. Giles, N. Sharac, M. G Spencer, and J. D Caldwell, ``Strong confinement of optical fields using localized surface phonon polaritons in cubic boron nitride ", Optics Letters 43, 2177 (2018)

[4] A. J. Giles, S. Dai, I. Vurgaftman, T. Hoffman, S. Liu, L. Lindsey, C. Ellis, N. Assefa, I. Chatzakis, T. L. Reinecke, J. G. Tischler, M. M. Fogler, J. H. Edgar, D. N. Basov, and J. D. Caldwell, `` Ultralow-loss polaritons in isotopically pure boron nitride ", Nature Materials 17, 134 (2018)

[5] I. Chatzakis, Z. Li, A. V. Benderskii, and S. B. Cronin, ``Broadband terahertz modulation in electrostatically-doped artificial trilayer graphene ", Nanoscale 9, 1721 (2017)

[6.] Z. Li, S. Yang, R. Dhall, E. Kosmowska, H. Shi, I. Chatzakis, and S. B. Cronin, ``Layer control of WSe2 via selective surface layer oxidation " American Chemical Society Nano 10, 6836, (2016)

[7] R. Dhall, K. Seyler, Z. Li, D. Wickramaratne, M. R. Neupane, I. Chatzakis, E. Kosmowska, R. K. Lake, X. Xu, and S. B. Cronin, ``Strong circularly polarized photoluminescence from multilayer MoS2 through plasma driven direct-gap transition ", American Chemical Society  Photonics 3, 310 (2016)

[8] Z. Li, G. Ezhilarasu, I. Chatzakis, C-C. Chen, R. Dhall, and S. B. Cronin, ``Indirect band gap emission by hot electron injection in metal/MoS2 and metal/WSe2 heterojunctions ", Nano Letters 15, 3977 (2015)

[9.] L. Luo, I. Chatzakis, A. Patz, and J. Wang, ``Ultrafast THz probes of interacting dark excitons in chirality-specific semiconducting single-wall carbon nanotubes ", Physical Review Letters 114, 107402 (2015)

[10.] M. J. Shu, P. Zalden, F. Chen, B. Weems, I. Chatzakis, F. Xiong, R. Jeyasingh, M.C. Hoffmann, E. Pop, H.-S. Philip Wong, M. Wutting, and A. M. Lindenberg, ``Ultrafast terahertz-induced response of GeSbTe phase-change materials  ", Applied Physics Letters 104, 201907 (2014)

[11.] L. Luo, I. Chatzakis, J. Wang, F. B. P. Niesler, M. Wegener, T. Koschny, and C. M. Soukoulis, ``Broadband terahertz generation from metamaterials ", Nature Communications 5, 3055 (2014)

[12.] I. Chatzakis, ``Electrons temperature dependence of the electron-phonon coupling strength in double-wall carbon nanotubes ", Applied Physics Letters 103, 043110 (2013)

[13.] M. J. Shu, I. Chatzakis, Y. Kuo, P. Zalden, and A. M. Lindenberg, ``Ultrafast sub-threshold photo-induced response in crystalline and amorphous GeSbTe thin films ", Applied Physics Letters 102, 201903 (2013)

[14.] I. Chatzakis, P. Tassin, L. Luo, N. H. Shen, L. Zhang, J. Wang, T. Koschny, and C. M. Soukoulis,``One-and two-dimensional photo-imprinted diffraction gratings for manipulating terahertz waves  ", Applied Physics Letters 103, 043101 (2013)
Selected as Cover Article for Applied Physics Letters (July 22, 2013; Issue 4)

[15.] I. Chatzakis, L. Luo, J. Wang, N-H. Shen, T. Koschny, J. Zhou, and C. M. Soukoulis,``Reversible modulation and ultrafast dynamics of terahertz resonances in strongly photoexcited metamaterials   ", Physical Review B, 86, 125110 (2012)

[16.] I. Chatzakis, H. Yan, D. Song, S. Berciaud, and T. Heinz,``Temperature dependence of the anharmonic decay rate of optical phonons in carbon nanotubes and graphite ", Physical Review B 83, 205411 (2011)

[17.] H. Yan, D. Song, K. F. Mak, I. Chatzakis, J. Maultzsch, and T. F. Heinz, ``Time-resolved Raman spectroscopy of optical phonons in graphite: Phonon anharmonic coupling and anomalous stiffening", Physical Review B 80, 121403 (2009)

[18.] T. J. M. Zouros, E. P. Benis, and I. Chatzakis, ``Optimization of the energy resolution of an ideal ESCA-type hemispherical analyzer", Nuclear Instruments and Methods in Physics Research Section B 235, 535 (2005)

Department of Physics and Astronomy