Coherent optical phonon oscillation and possible electronic softening in WTe2 crystals
| Autor: | Shenghua Liu, Min Xiao, Yufeng Li, Chunfeng Zhang, Hai-Hu Wen, Xiaoyong Wang, X. S. Wu, Xiyu Zhu, Bin He, Weida Zhu |
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| Rok vydání: | 2016 |
| Předmět: |
Multidisciplinary
Materials science Condensed matter physics Phonon Anharmonicity Giant magnetoresistance 02 engineering and technology Electron Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences Article Condensed Matter::Materials Science Condensed Matter::Superconductivity Lattice (order) 0103 physical sciences Condensed Matter::Strongly Correlated Electrons 010306 general physics 0210 nano-technology Spectroscopy Ultrashort pulse Excitation |
| Zdroj: | Scientific Reports |
| ISSN: | 2045-2322 |
| DOI: | 10.1038/srep30487 |
| Popis: | A rapidly-growing interest in WTe2 has been triggered by the giant magnetoresistance effect discovered in this unique system. While many efforts have been made towards uncovering the electron- and spin-relevant mechanisms, the role of lattice vibration remains poorly understood. Here, we study the coherent vibrational dynamics in WTe2 crystals by using ultrafast pump-probe spectroscopy. The oscillation signal in time domain in WTe2 has been ascribed as due to the coherent dynamics of the lowest energy A1 optical phonons with polarization- and wavelength-dependent measurements. With increasing temperature, the phonon energy decreases due to anharmonic decay of the optical phonons into acoustic phonons. Moreover, a significant drop (15%) of the phonon energy with increasing pump power is observed which is possibly caused by the lattice anharmonicity induced by electronic excitation and phonon-phonon interaction. |
| Databáze: | OpenAIRE |
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