Many-body recombination in photoexcited insulating cuprates

Sahota, Derek G.; Liang, Ruixing; Dion, Maxime; Fournier, P.; Dąbkowska, H. A.; Luke, G. M.; Dodge, J. Steven

doi:10.1103/physrevresearch.1.033214

Cited by 15 publications

(11 citation statements)

References 36 publications

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“…Advances in theory and experimental techniques have begun to address these questions, indicating for example that the recombination rates are proportional to the MH gap and mediated by magnon emission [11][12][13][14]. Ultrafast optical spectroscopy is a technique particularly well suited to furthering our understanding of this field, and has been used extensively to study ultrafast dynamics in many MH insulators, including cuprates [15][16][17], manganites [18,19], and TaS 2 [20].…”

Section: Introductionmentioning

confidence: 99%

Influence of spin and orbital fluctuations on Mott-Hubbard exciton dynamics in LaVO3 thin films

et al. 2020

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Recent optical conductivity measurements reveal the presence of Hubbard excitons in certain Mott insulators. In light of these results, it is important to revisit the dynamics of these materials to account for excitonic correlations. We investigate time-resolved excitation and relaxation dynamics as a function of temperature in perovskite-type LaVO 3 thin films using ultrafast optical pump-probe spectroscopy. LaVO 3 undergoes a series of phase transitions at roughly the same critical temperature T C ∼ = 140 K, including a second-order magnetic phase transition (PM − → AFM) and a first-order structural phase transition, accompanied by C-type spin order and G-type orbital order. Ultrafast optical pump-probe spectroscopy at 1.6 eV monitors changes in the spectral weight of the Hubbard exciton resonance which serves as a sensitive reporter of spin and orbital fluctuation dynamics. We observe dramatic slowing down of the spin, and orbital dynamics in the vicinity of T C ∼ = 140 K, reminiscent of a second-order phase transition, despite the (weakly) first-order nature of the transition. We emphasize that since it is spectral weight changes that are probed, the measured dynamics are not reflective of conventional exciton generation and recombination, but are related to the dynamics of Hubbard exciton formation in the presence of a fluctuating many-body environment.

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Section: Introductionmentioning

confidence: 99%

Influence of spin and orbital fluctuations on Mott-Hubbard exciton dynamics in LaVO3 thin films

et al. 2020

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“…Here we see dramatically different behavior for 800 versus 400 nm excitation: the peak differential transmission increases sublinearly with 400 nm and superlinearly with 800 nm excitation. As we have already argued that two-photon absorption is not the dominant excitation channel for 800 nm excitation (see Section S8, Supporting Information), we instead attribute the super-linear behavior at low fluence to trapping on timescales faster than the system response time, [72] which is approximately 0.4 ps.…”

Section: Trap Filling Dynamics and Defect Densitymentioning

confidence: 91%

“…To understand the saturation behavior with 400 nm excitation, we can rule out the introduction of new recombination channels as the lifetime does not decrease with increasing fluence. [72] We can also rule out optical nonlinearities (see Section S8, Supporting Information) and reduction of mobility at high fluence (see Section S11, Supporting Information). At high fluences the carrier density is greater than 10 18 cm −3 (see Section S11, Supporting Information), which is high enough that the quasi-Fermi level is pushed into the conduction band where the dispersion is highly non-parabolic.…”

Section: Trap Filling Dynamics and Defect Densitymentioning

confidence: 99%

Ultrafast Photoconductivity and Terahertz Vibrational Dynamics in Double‐Helix SnIP Nanowires

et al. 2021

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SnIP could be the first of a new class of inorganic double-helix materials. [7][8][9] With strong intra-helix covalent bonds and weak inter-helix dispersion forces, SnIP belongs to the group of newly emerging 1D van der Waals (vdW) materials with potential applications in nanoelectronics and photonics. [10][11][12][13] In contrast to the DNA structure, which consists of two equal radius helices, SnIP forms with an outer [SnI] + helix wrapping around an inner [P] − helix, as pictured in Figure 1a. SnIP crystallizes monoclinically with a unit cell containing two opposite-handed double helices so that there is no net chirality. It is composed of abundant and non-toxic elements and can grow uninhibited to cm-length needles with a low-temperature synthesis [6,14] (Sections S1 and S2, Supporting Information) or in nanotubes using vapor deposition. [15,16] Its 1.86 eV band gap, as determined by band structure calculations (Figure 1b,c) and verified experimentally (see ref.[ 6 ] and Section S3, Supporting Information), is well situated for solar absorption and photocatalytic water splitting. [8,10,15] SnIP is also an extremely soft and flexible semiconductor and is therefore a promising material for applications in flexible electronics, [6,10] where these properties are highly desirable. [17] It is predicted to have a high carrier mobility; [8] however, as-grown SnIP is highly resistive so that the current lack of doped samples has made it difficult to explore its electronic properties. [6] Moreover, despite the exciting properties and unique structure of SnIP, there have been no investigations probing its ultrafast photophysical properties.Here, we use time-resolved terahertz (THz) spectroscopy (TRTS) to study picosecond charge carrier dynamics in SnIP nanowire films, as shown in Figure 1d. TRTS, a powerful non-contact ultrafast probe, has been used extensively to probe carrier dynamics in low-dimensional materials, accelerating scientific understanding of transport mechanisms and enabling materials optimization for potential applications. [18,19] From analysis of the photoconductivity spectra, along with insight into the highly anisotropic energy landscape from density functional theory (DFT), we make the first measurement of the carrier mobility in SnIP. We find a maximum electron mobility of 280 cm 2 V −1 s −1 along the double-helix axis, an extraordinarily high mobility for a material as soft and flexible as SnIP. On Tin iodide phosphide (SnIP), an inorganic double-helix material, is a quasi-1D van der Waals semiconductor that shows promise in photocatalysis and flexible electronics. However, the understanding of the fundamental photophysics and charge transport dynamics of this new material is limited. Here, time-resolved terahertz (THz) spectroscopy is used to probe the transient photoconductivity of SnIP nanowire films and measure the carrier mobility. With insight into the highly anisotropic electronic structure from quantum chemical calculations, an electron mobility as high as 280 cm 2 V −1 s −1 along the doub...

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“…For example, doped Mott insulators show strange metallic behaviors without well-defined Fermi liquid quasiparticles in a wide parameter regime 18,19 , and similar behavior is observed in photo-doped Mott insulators. [20][21][22][23][24] Furthermore, the electronic structure in correlated systems depends strongly on the non-equilibrium distribution, as most clearly demonstrated through the possibility of photo-induced metal insulator transitions.…”

Section: Introductionmentioning

confidence: 99%

A quantum Boltzmann equation for strongly correlated electrons

Picano,

Li,

Eckstein

2021

Preprint

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Collective orders and photo-induced phase transitions in quantum matter can evolve on timescales which are orders of magnitude slower than the femtosecond processes related to electronic motion in the solid. Quantum Boltzmann equations can potentially resolve this separation of timescales, but are often constructed within a perturbative framework. Here we derive a quantum Boltzmann equation which only assumes a separation of timescales (taken into account through the gradient approximation for convolutions in time), but is based on a non-perturbative scattering integral, and makes no assumption on the spectral function such as the quasiparticle approximation. In particular, a scattering integral corresponding to non-equilibrium dynamical mean-field theory is evaluated in terms of an Anderson impurity model in a non-equilibrium steady state with prescribed distribution functions. This opens the possibility to investigate dynamical processes in correlated solids with quantum impurity solvers designed for the study of non-equilibrium steady states.

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Many-body recombination in photoexcited insulating cuprates

Cited by 15 publications

References 36 publications

Influence of spin and orbital fluctuations on Mott-Hubbard exciton dynamics in LaVO3 thin films

Influence of spin and orbital fluctuations on Mott-Hubbard exciton dynamics in LaVO3 thin films

Ultrafast Photoconductivity and Terahertz Vibrational Dynamics in Double‐Helix SnIP Nanowires

A quantum Boltzmann equation for strongly correlated electrons

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