Engineering crystal structures with light

Disa, Ankit; Nova, Tobia F.; Cavalleri, Andrea

doi:10.1038/s41567-021-01366-1

Cited by 133 publications

(65 citation statements)

References 74 publications

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“…We do note that due to the spectral coverage of commercial optical parametric amplifiers (OPAs), the proposed method does not readily apply to inorganic materials that lack vibrational modes 13 shorter than 16 µm (i.e., 625 cm -1 ), although far-infrared OPAs and intense terahertz source are being actively developed for coherent phonon excitations of solids with vibrational modes in the corresponding spectral ranges. 57,58…”

Section: Discussionmentioning

confidence: 99%

Time-resolved vibrational-pump visible-probe spectroscopy for thermal conductivity measurement of metal-halide perovskites

Dai

et al. 2022

Review of Scientific Instruments

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Understanding thermal transport at the microscale to the nanoscale is crucially important for a wide range of technologies ranging from device thermal management and protection systems to thermal-energy regulation and harvesting. In the past decades, non-contact optical methods, such as time-domain and frequency-domain thermoreflectance, have emerged as extremely powerful and versatile thermal metrological techniques for the measurement of material thermal conductivities. Here, we report the measurement of thermal conductivity of thin films of CH3NH3PbI3 (MAPbI3), a prototypical metal-halide perovskite, by developing a time-resolved optical technique called vibrational-pump visible-probe (VPVP) spectroscopy. The VPVP technique relies on the direct thermal excitation of MAPbI3 by femtosecond mid-infrared optical pump pulses that are wavelength-tuned to a vibrational mode of the material, after which the time dependent optical transmittance across the visible range is probed in the ns to the μs time window using a broadband pulsed laser. Using the VPVP method, we determine the thermal conductivities of MAPbI3 thin films deposited on different substrates. The transducer-free VPVP method reported here is expected to permit spectrally resolving and spatiotemporally imaging of the dynamic lattice temperature variations in organic, polymeric, and hybrid organic–inorganic semiconductors.

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Section: Discussionmentioning

confidence: 99%

Time-resolved vibrational-pump visible-probe spectroscopy for thermal conductivity measurement of metal-halide perovskites

Dai

et al. 2022

Review of Scientific Instruments

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“…On the other hand, efficient absorption in the freestanding membranes could stabilize the optically induced transient phases, such as metastable ferroelectricity in paraelectric SrTiO 3 [240] or superconductivity in cuprates [241]. These phases are induced by targeting a specific mid-infrared phonon in TMO [242], yet substrate clamping can increase the phonon decay rates making the suspended samples preferrable to prolong the phase lifetimes. Moreover, the symmetric geometry of the freestanding TMO membranes would allow for the creation of nanocavities for the material's phase control via interaction with the photon vacuum fields that would not require direct optical pumping (figure 8(b)) [243].…”

Section: Light-matter Interactionsmentioning

confidence: 99%

Freestanding complex-oxide membranes

Pesquera

Fernández

Khestanova

et al. 2022

J. Phys.: Condens. Matter

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Complex oxides show a vast range of functional responses, unparalleled within the inorganic solids realm, making them promising materials for applications as varied as next-generation field-effect transistors, spintronics, electro-optic modulators, pyroelectric detectors, or oxygen reduction catalysts. Their stability in ambient conditions, chemical versatility, and large susceptibility to minute structural and electronic modifications make them ideal subjects of study to discover emergent phenomena and to generate novel functionalities for next-generation devices. Recent advances in the synthesis of single-crystal, freestanding complex oxide membranes provide an unprecedented opportunity to study these materials in a nearly-ideal system (e.g., free of mechanical/thermal interaction with substrates) as well as expanding the range of tools for tweaking their order parameters (i.e., (anti-)ferromagnetic, (anti-)ferroelectric, ferroelastic), and increasing the possibility of achieving novel heterointegration approaches (including interfacing dissimilar materials) by avoiding the chemical, structural, or thermal constraints in synthesis processes. Here, we review the recent developments in the fabrication and characterization of complex-oxide membranes and discuss their potential for unraveling novel physicochemical phenomena at the nanoscale and for futher exploiting their functionalities in technologically relevant devices.

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“…Selective excitation of finite momentum X-point phonons requires considerable effort (30)(31)(32), with the experimentally easily accessible phonon excitations being the IR active phonon modes at -point. While the equilibrium EPC is negligible for these phonons, a key finding thus far is that, by itself, this cannot serve as a means to predict the strength of the dynamic coupling between preexcited phonons and demagnetization.…”

Section: Ir Active Phononsmentioning

confidence: 99%

Making a case for femto-phono-magnetism with FePt

et al. 2022

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In the field of femtomagnetism, magnetic matter is controlled by ultrafast laser pulses; here, we show that coupling phonon excitations of the nuclei to spin and charge leads to femto-phono-magnetism, a powerful route to control magnetic order at ultrafast times. With state-of-the-art theoretical simulations of coupled spin, charge, and lattice dynamics, we identify strong nonadiabatic spin-phonon coupled modes that dominate early time spin dynamics. Activating these phonon modes that we show leads to an additional (up to 40% extra) loss of moment in iron-platinum occurring within 40 femtoseconds of the pump laser pulse. Underpinning this enhanced ultrafast loss of spin moment, we identify a physical mechanism in which minority spin current drives an enhanced intersite minority charge transfer, in turn promoting increased on-site spin flips. Our finding demonstrates that the nuclear system, often assumed to play the role of an energy and angular momentum sink, when selectively preexcited, can play a profound role in controlling femtosecond spin dynamics in materials.

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Engineering crystal structures with light

Cited by 133 publications

References 74 publications

Time-resolved vibrational-pump visible-probe spectroscopy for thermal conductivity measurement of metal-halide perovskites

Time-resolved vibrational-pump visible-probe spectroscopy for thermal conductivity measurement of metal-halide perovskites

Freestanding complex-oxide membranes

Making a case for femto-phono-magnetism with FePt

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