Fahad Mahmood

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Biography

Professor Fahad Mahmood is an experimentalist in condensed matter physics. He started his research lab on the femtosecond manipulation of quantum materials at the University of Illinois in August 2019. He received his B.S. from Stanford University in 2010, majoring in Physics and Aero/Astro Engineering. He went on to receive his PhD in Physics from the Massachusetts Institute of Technology in 2016, working in the group of Nuh Gedik. There, he developed ultrafast optical and photoemission techniques to study and control emergent phenomena in a variety of quantum materials. From 2016 to 2019, Professor Mahmood was a postdoctoral research fellow in the group of Peter Armitage at Johns Hopkins University. His research used THz range spectroscopies to probe complex interactions in high-temperature and unconventional superconductors, and frustrated quantum magnets at their natural energy scales.

Research Statement

Professor Fahad Mahmood's research lab at the University of Illinois will develop and apply non-linear optical and time-resolved photoemission spectroscopies to solve problems at the intersection of strongly correlated quantum materials and non-equilibrium phenomena. One of the principal goals is to use laser light to engineer electronic interactions in materials, probe their spatial and temporal correlations, and realize model Hamiltonians and novel phases of matter.

Typical experiments will use a laser pulse to perturb a particular material in different ways, e.g., by coupling to charge or spin degrees of freedom, exciting specific collective modes or modifying the local energy landscape over short (femtosecond) timescales. Custom-built spectroscopic tools such as time-resolved ARPES and time-domain THz spectroscopy will then be used to examine the resulting evolution of electronic states, measure changes in low-energy electrodynamics and disentangle coupled excitations. Projects and materials will be varied but will likely include unconventional superconductors, topological systems and frustrated magnets.

Selected Articles in Journals

• Transport and optical properties of the chiral semiconductor Ag3AuSe2. Juyeon Won, Soyeun Kim, Martin Gutierrez-Amigo, Simon Bettler, Bumjoo Lee, Jaeseok Son, Tae Won Noh, Ion Errea, Maia G. Vergniory, Peter Abbamonte, Fahad Mahmood, Daniel P. Shoemaker. Z. Anorg. Allg. Chem. (2022)
• Effect of radiation-induced defects on the superfluid density and optical conductivity of overdoped La2−xSrxCuO. Fahad Mahmood, David Ingram, Xi He, J. A. Clayhold, Ivan Bozovic, N.P. Armitage. Physics Review B 105, 174501 (2022)
• Distinguishing finite momentum superconducting pairing states with two-electron photoemission spectroscopy. Fahad Mahmood, Thomas Devereaux, Peter Abbamonte, and Dirk K. Morr. Physics Review B 105, 064515 (2022)
• BCS d-wave behavior in the terahertz electrodynamic response of electron-doped cuprate superconductors. Zhenisbek Tagay, Fahad Mahmood, Anaelle Legros, Tarapada Sarkar, Richard L. Greene, and N. P. Armitage. Physics Review B 104, 064501 (2021)
• Observation of a marginal Fermi glass. Fahad Mahmood, Dipanjan Chaudhuri, Sarang Gopalakrishnan, Rahul Nandkishore, N. P. Armitage. Nature Physics 17, 627-631 (2021)
• Tunable Magnon Interactions in a Ferromagnetic Spin-1 Chain. Prashant Chauhan, Fahad Mahmood, Hitesh J. Changlani, Seyed M. Koohpayeh, N. P. Armitage. Physical review letters 124 (3), 037203 (2020)
• Nodeless bulk superconductivity in the time-reversal symmetry breaking Bi/Ni bilayer system. Prashant Chauhan, Fahad Mahmood, Di Yue, Peng-Chao Xu, Xiaofeng Jin, and N. P. Armitage. Physical Review Letters 122, 017002 (2019)
• Locating the missing superconducting electrons in the overdoped cuprates La2-xSrxCuO4. Fahad Mahmood, Xi He, Ivan Bozovic and N.P. Armitage. Physical Review Letters 122, 027003 (2019)
• Hierarchy of exchange interactions in the triangular-lattice spin-liquid YbMgGaO4. Xinshu Zhang, Fahad Mahmood, Marcus Daum, Zhiling Dun, J. A. M. Paddison, N. J. Laurita, Tao Hong, Haidong Zhou, N. P. Armitage and Martin Mourigal. Physical Review X 8, 031001 (2018)
• Observation of exciton-exciton interaction mediated valley depolarization in monolayer MoSe2. Fahad Mahmood, Zhanybek Alpichshev, Yi-Hsien Lee, Jing Kong and Nuh Gedik. Nano Letters 18, 223 (2018)
• The origin of exciton mass in a frustrated Mott insulator Na2IrO3. Zhanybek Alpichshev, Edbert J. Sie, Fahad Mahmood, Gang Cao and Nuh Gedik. Physical Review B 96, 235141 (2017)
• Ultrafast dynamics in the presence of antiferromagnetic correlations in electrondoped cuprate La2−xCexCuO4±δ. Inna M. Vishik, Fahad Mahmood, Zhanybek Alpichshev, Nuh Gedik, J. Higgins and R. L. Greene. Physical Review B 95, 115125 (2017)
• The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors. J. P. Hinton, E. Thewalt, Z. Alpichshev, Fahad Mahmood, J. D. Koralek, M. K. Chan, M. J. Veit, C. J. Dorow, N. Barisic, A. F. Kemper, D. A. Bonn, W. N. Hardy, R. Liang, N. Gedik, M. Greven, A. Lanzara, J. Orenstein. Scientific Reports 6, 23610 (2016)
• Selective scattering between Floquet-Bloch and Volkov states in a topological insulator. Fahad Mahmood, Ching-Kit Chan, Dillon R. Gardner, Young S. Lee, Patrick Lee and Nuh Gedik. Nature Physics 12, 306310 (2016)
• Confinement-deconfinement transition as an indication of spin-liquid-type behavior in Na2IrO3. Zhanybek Alpichshev, Fahad Mahmood, Gang Cao and Nuh Gedik. Physical Review Letters 114, 017203 (2014)
•  Electrostatic Coupling between Two Surfaces of a Topological Insulator Nanodevice. Valla Fatemi, Benjamin Hunt, Hadar Steinberg, Stephen L Eltinge, Fahad Mahmood, Nicholas P Butch, Kenji Watanabe, Takashi Taniguchi, Nuh Gedik, Raymond C Ashoori and Pablo Jarillo-Herrero. Physical Review Letters 113, 206801 (2014)
• Fluctuating charge density waves in a cuprate superconductor. Darius Torchinsky*, Fahad Mahmood*, Anthony T. Bollinger, Ivan Boovic, and Nuh Gedik. Nature Materials 12, 387-391 (2013)
• Observation of a metal-to-insulator transition with both Mott-Hubbard and Slater characteristics in Sr2IrO4 from time-resolved photocarrier dynamics. David Hsieh, Fahad Mahmood, Darius Torchinsky, Gang Cao and Nuh Gedik. Physical Review B 86, 035128 (2012)
• Selective probing of photoinduced charge and spin dynamics in the bulk and surface of a topological insulator. David Hsieh, Fahad Mahmood, James W. McIver, D. R. Gardner, Y. S. Lee, and Nuh Gedik. Physical Review Letters 107, 077401 (2011)