Ultrafast Terahertz Probes of Interacting Dark Excitons in Chirality-Specific Semiconducting Single-Walled Carbon Nanotubes

Luo, Liang; Chatzakis, Ioannis; Patz, Aaron; Wang, Jigang

doi:10.1103/physrevlett.114.107402

Cited by 54 publications

(41 citation statements)

References 39 publications

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“…2b) and dielectric function Δ ɛ 1 ( ω ) (Fig. 2c), associated with dissipative and inductive responses of the sample31 (also see Methods and Supplementary Note 3). At high temperature above the structural phase transition at T S =160 K, the 295 K trace exhibits two strong photoinduced bleaching features, that is, negative conductivity (Δ σ 1 <0), at 4.2 and 10 meV.…”

Section: Resultsmentioning

confidence: 93%

“…We perform optical-pump and THz-probe spectroscopy, which is driven by a 1 kHz Ti:Sapphire regenerative amplifier with 790 nm central wavelength and 40 fs pulse duration22233031. One part of the output is used to pump the sample either directly at the fundamental wavelength of 790 nm or at 399 nm after going through a β -barium-borate (BBO) crystal.…”

Section: Resultsmentioning

confidence: 99%

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Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite

et al. 2017

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How photoexcitations evolve into Coulomb-bound electron and hole pairs, called excitons, and unbound charge carriers is a key cross-cutting issue in photovoltaics and optoelectronics. Until now, the initial quantum dynamics following photoexcitation remains elusive in the hybrid perovskite system. Here we reveal excitonic Rydberg states with distinct formation pathways by observing the multiple resonant, internal quantum transitions using ultrafast terahertz quasi-particle transport. Nonequilibrium emergent states evolve with a complex co-existence of excitons, carriers and phonons, where a delayed buildup of excitons under on- and off-resonant pumping conditions allows us to distinguish between the loss of electronic coherence and hot state cooling processes. The nearly ∼1 ps dephasing time, efficient electron scattering with discrete terahertz phonons and intermediate binding energy of ∼13.5 meV in perovskites are distinct from conventional photovoltaic semiconductors. In addition to providing implications for coherent energy conversion, these are potentially relevant to the development of light-harvesting and electron-transport devices.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite

et al. 2017

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“…It has been argued theoretically that the optical transition energy of a SWNT can be written as the sum of a one-particle energy term and a many-body one, which in turn is decomposed into selfenergy, due to electron-electron interactions, and an exciton binding energy [2][3][4][5][6]. These predictions have been validated by means of various experiments, including two-photon absorption [7,8], photoluminescence excitation experiments on semiconducting SWNTs (S-SWNT) [9], absorption experiments on S-SWNTs and on metallic SWNTs (M-SWNT) [10][11][12], Rayleigh scattering experiments [13][14][15], scanning tunneling spectroscopy [16], and, recently, ultrafast terahertz spectroscopy [17].…”

Section: Introductionmentioning

confidence: 99%

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

et al. 2016

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We examine the excitonic nature of the E 33 optical transition of the individual free-standing index-identified (23,7) single-walled carbon nanotube by means of the measurements of its radial-breathing-mode and G-mode Raman excitation profiles. We confirm that it is impossible to determine unambiguously the nature of its E 33 optical transition (excitonic vs band to band) based only on the excitation profiles. Nevertheless, by combining Raman scattering, Rayleigh scattering, and optical absorption measurements on strictly the same individual (23,7) single-walled carbon nanotube, we show that the absorption, Rayleigh spectra, and Raman excitation profiles of the longitudinal and transverse G modes are best fitted by considering the nature of the E 33 transition as excitonic. The fit of the three sets of data gives close values of the transition energy E 33 and damping parameter 33 . This comparison shows that the fit of the Raman excitation profiles provides with good accuracy the energy and damping parameter of the excitonic optical transitions in single-walled carbon nanotubes.

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“…The insights from our theoryexperiment results and our proposed "sudden quench" mechanism based on the "soft" quasi-particle energy bands may also prove useful for revealing the crucial many-body processes in other intertwined electronic phases, as the proximity of magnetic states appears ubiquitous with unconventional superconducting and exotic electronic phases in strongly correlated electronic materials [16]. In the long run, new insights can be gained by applying complementary ultrafast spectroscopy techniques, especially in the terahertz [57] and infrared spectral regions [58], and by combining spin and charge quantum fluctuations with quasi-equilibrium free energy and selfenergy effects. σ=1 (-1) means quasi-particle total spin parallel (antiparallel) to the equilibrium spin direction determined by θi=0 or π.…”

Section: Discussionmentioning

confidence: 99%

Correlating quasiparticle excitations with quantum femtosecond magnetism in photoexcited nonequilibrium states of insulating antiferromagnetic manganites

Lingos

Patz

et al. 2017

Phys. Rev. B

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We describe a mechanism for insulator-to-metal transition triggered by spin-canting following fs laserexcitation of insulating anti-ferromagnetic (AFM) states of colossal magneto-resistive (CMR) manganites. We show that photoexcitation of composite fermion quasi-particles dressed by spin fluctuations results in the population of a broad metallic conduction band due to canting of the AFM background spins via strong electron-spin local correlation. By inducing spin-canting, photoexcitation can increase the quasi-particle energy dispersion and quench the charge excitation energy gap. This increases the critical Jahn-Teller (JT) lattice displacement required to maintain an insulating state. We present fs-resolved pump-probe measurements showing bi-exponential relaxation of the differential reflectivity below the AFM transition temperature. We observe a nonlinear dependence of the ratio of the fs and ps relaxation component amplitudes at the same pump fluence threshold where we observe femtosecond magnetization photoexcitation. We attribute this correlation between nonlinear fs spin and charge dynamics to spin/charge/lattice coupling and population inversion between the polaronic majority carriers and metallic quasi-electron minority carriers as the lattice displacement becomes smaller than the critical value required to maintain an insulating state following laser-induced spin canting.

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Ultrafast Terahertz Probes of Interacting Dark Excitons in Chirality-Specific Semiconducting Single-Walled Carbon Nanotubes

Cited by 54 publications

References 39 publications

Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite

Ultrafast terahertz snapshots of excitonic Rydberg states and electronic coherence in an organometal halide perovskite

Excitonic optical transitions characterized by Raman excitation profiles in single-walled carbon nanotubes

Correlating quasiparticle excitations with quantum femtosecond magnetism in photoexcited nonequilibrium states of insulating antiferromagnetic manganites

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