TY - JOUR
T1 - Coherent Dirac plasmons in topological insulators
AU - Mondal, Richarj
AU - Arai, Akira
AU - Saito, Yuta
AU - Fons, Paul
AU - Kolobov, Alexander V.
AU - Tominaga, Junji
AU - Hase, Muneaki
N1 - Funding Information:
This research was financially supported by Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Grant No. JPMJCR14F1, and Japan Society for the Promotion of Science (JSPS) KAKENHI, Grant No. 17H02908. We acknowledge Ms. R. Kondou for sample preparation.
PY - 2018/4/24
Y1 - 2018/4/24
N2 - We explore the ultrafast reflectivity response from photo-generated coupled phonon-surface Dirac plasmons in Sb2Te3 topological insulators several quintuple layers thick. The transient coherent phonon spectra obtained at different time frames exhibit a Fano-like asymmetric line shape of the A1g2 mode, which is attributed to quantum interference between continuumlike coherent Dirac plasmons and phonons. By analyzing the time-dependent asymmetric line shape using the two-temperature model (TTM), it was determined that a Fano-like resonance persisted up to ≈1 ps after photo excitation with a relaxation profile dominated by Gaussian decay at ≤200 fs. The asymmetry parameter could be well described by the TTM for ≥200 fs, therefore suggesting the coherence time of the Dirac plasmon is ≈200 fs.
AB - We explore the ultrafast reflectivity response from photo-generated coupled phonon-surface Dirac plasmons in Sb2Te3 topological insulators several quintuple layers thick. The transient coherent phonon spectra obtained at different time frames exhibit a Fano-like asymmetric line shape of the A1g2 mode, which is attributed to quantum interference between continuumlike coherent Dirac plasmons and phonons. By analyzing the time-dependent asymmetric line shape using the two-temperature model (TTM), it was determined that a Fano-like resonance persisted up to ≈1 ps after photo excitation with a relaxation profile dominated by Gaussian decay at ≤200 fs. The asymmetry parameter could be well described by the TTM for ≥200 fs, therefore suggesting the coherence time of the Dirac plasmon is ≈200 fs.
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U2 - 10.1103/PhysRevB.97.144306
DO - 10.1103/PhysRevB.97.144306
M3 - Article
AN - SCOPUS:85046745436
VL - 97
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 2469-9950
IS - 14
M1 - 144306
ER -