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Updated: Jun 13, 2025
Measurement of Coherence Decay in GaMnAs Using Femtosecond Four-wave Mixing
Published on: December 3, 2013
Optical Conductivity and Photo-Induced Polaronic Formation in Co2MnGa Topological Semimetal
Luca Tomarchio1,2, Salvatore Macis1, Sen Mou2
1Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185, Rome, Italy.
Abstract:
Topological materials occupy an important place in the quantum materials family due to their peculiar low-energy electrodynamics, hosting emergent magneto-electrical, and nonlinear optical responses. This manuscript reports on the optical responses for the magnetic topological nodal semimetal Co2MnGa, studied in a thin film geometry at various thicknesses. The thickness-dependent optical conductivity is investigated, observing a substantial dependence of the electronic band structure on thickness. Additionally, details on the ultrafast response of the low energy excitations in the terahertz frequency are reported by employing optical pump-terahertz probe (OPTP) spectroscopy. In particular, the photocarrier dynamics of Co2MnGa thin films is studied at varying pump fluence, pump wavelength, and film thickness, observing a negative THz photoconductivity which is assigned to a dynamical formation of large polarons in the material.
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