Ionic-to-neutral phase transformation induced by photoexcitation of the charge-transfer band in tetrathiafulvalene-<i>p</i>-chloranil crystals

Suzuki, Toshio; Sakamaki, T.; Tanimura, Katsumi; Koshihara, Shin‐ya; Tokura, Y.

doi:10.1103/physrevb.60.6191

Cited by 72 publications

(75 citation statements)

References 10 publications

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“…A comparison with previous measurements, which are presented in Figure 26, reveals that the observed linear behavior of ∆ t R(0) agrees very well with the study of Suzuki et al [85]. There, the change of reflectivity was measured at 24,200 cm −1 .…”

Section: Photo-induced Phase Transitionsupporting

confidence: 79%

“…In principle, excitations from lower lying bands into the valence band are also possible; however these are not included here. Suzuki et al [85] compared the dependence of the conversion efficiency on the photon energy (see Figure 26 below) and found that by excitation of intramolecular transitions, no threshold intensity occurs to create neutral domains.…”

Section: Underlying Principlementioning

confidence: 99%

“…Beside temperature, the dependence of the PIPTs on the photon energy was examined in the near-infrared range. It was demonstrated that the laser pulses with a photon energy E Photon between 0.65 eV and 1.55 eV must exceed a certain threshold intensity [85,86,88] to induce the neutral domains. The photon energy corresponds in this case to the energyhω CT of the charge-transfer band/exciton (CT) which we have identified in the spectrum as a broad maximum at 5200 cm −1 (0.65 eV).…”

Section: Underlying Principlementioning

confidence: 99%

“…From that, we can deduce that in both cases the conductivity contributions are thermally activated or optically excited NIDWs, respectively. This pioneer ingreport [69] triggered numerous studies [70,76,[85][86][87] of the PIPT aiming to examine the creation process of the neutral domains in the ionic phase. Most of the studies were performed at two temperatures: either very close to the transition (approximately 78 K) or for a very low temperature (∼4 K).…”

Section: Underlying Principlementioning

confidence: 99%

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Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Dressel

Peterseim

2017

Crystals

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Abstract:The neutral-ionic phase transition in TTF-CA was investigated by steady-state and time-resolved infrared spectroscopy. We describe the growth of high-quality single crystals and their characterization. Extended theoretical calculations were performed in order to obtain the band structure, the molecular vibrational modes and the optical spectra along all crystallographic axes. The theoretical results are compared to polarization-dependent infrared reflection experiments. The temperature-dependent optical conductivity is discussed in detail. We study the photo-induced phase transition in the vicinity of thermally-induced neutral-ionic transition. The observed temporal dynamics of the photo-induced states is attributed to the random-walk of neutral-ionic domain walls. We simulate the random-walk annihilation process of domain walls on a one-dimensional chain.

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Section: Photo-induced Phase Transitionsupporting

confidence: 79%

Section: Underlying Principlementioning

confidence: 99%

Section: Underlying Principlementioning

confidence: 99%

Section: Underlying Principlementioning

confidence: 99%

See 2 more Smart Citations

Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Dressel

Peterseim

2017

Crystals

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“…Similar results have been obtained for 1D and 3D superstructures. The existence of a threshold light intensity for the photoinduced phase transition was also suggested in real materials [3,10]. The threshold W c at which t p diverges is reduced drastically with increasing |∆|.…”

Section: (B))mentioning

confidence: 89%

Conceptual design of nanostructures for efficient photoinduced phase transitions

Kawamoto

Abe

2002

Applied Physics Letters

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By means of Monte Carlo simulations on a kinetic model, we demonstrate that the efficiency of a photoinduced phase change can in general be enhanced drastically by using a superstructure of an appropriate combination of two components. This is due to the accelerated nucleation of converted domains in the structural blocks relatively close to local instability. The present mechanism provides a general guideline on the design of photocontrollable materials with potential applications for memory and storage devices.Control of material phases by external stimuli, especially by light, has been a subject of much interest in recent years in view of potential applications for memory and storage devices in the future. It requires a material exhibiting bistability between two distinct phases. In many cases the global bistability of a solid has a local origin [1][2][3][4], while the photo-conversion between phases usually proceeds in a cooperative fashion [3,4]. This phenomenon is therefore called a photoinduced phase transition, in analogy with ordinary (thermally induced) phase transitions.The actual observation of the phenomenon has been limited within a small number of materials: one or a few examples from each class of materials, including spincrossover complexes [3], Prussian blue analogues [1,5], organic charge-transfer complexes [4] and conjugated polymers [6]. The scarcity of materials is presumably related to the requirement that the two phases must be energetically close to each other, otherwise the metastable phase would return to the stable phase quickly.Here we propose a general scheme to overcome this difficulty. Suppose we have a bistable material α in which the metastable state B is much higher in energy than the stable state A, so that photo-conversion is difficult. Let us then prepare a companion material β in which the relative stability is opposite (see Fig.1(a)). If we combine the two materials in an appropriate fashion, e.g., in a superlattice as shown in Fig.1(b), and if there are sufficient cooperative interactions that favor the α and β units being in the same state (either A or B), then the energy of the A phase in the total system can be made degenerate with that of the B phase. This is rather an obvious way of designing new suitable materials in general. However, this approach yields more than that: We will demonstrate in the following that the photo-conversion efficiently is drastically enhanced in such mixed structures compared with uniform structures.We consider a phenomenological model described by the Ising Hamiltonian [7,8] on a three-dimensional lattice, where the 'spin' variable S i = ±1 denotes the two states (B and A) of the site i with the energy difference 2ε i . The nearest neighbor (n.n.) coupling J ij is assumed to be a positive constant J, so that the neighboring sites prefer to be in the same state. We use a simple cubic lattice of N × N × N sites with periodic boundary conditions. N = 60 is a typical size used in our simulations. We consider the superstructures consisting of t...

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Appearance of a Photoinduced Hidden State in the Electron Donor–Acceptor Type Metal–Organic Framework (NPr₄)₂[Fe₂(Cl₂An)₃]

Banu,

Kato,

Takubo

et al. 2023

Advanced Optical Materials

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Electron donor–acceptor (DA)‐type metal–organic frameworks (MOFs) with valence instability are promising molecular materials for the design of photo‐responsive and electronic/magnetic functional materials. Here, ultrafast photoinduced dynamics in a DA‐type layered MOF that exhibits a charge‐transfer (CT)‐type phase transition are reported: (NPr4)2[Fe2(Cl2An)3], where NPr4+ = tetra‐n‐propylammonium and Cl2An2− = 2,5‐dichloro‐3,6‐dihydroxo‐1,4‐benzoquinonate. At room temperature (300 K: RT), ultrafast photoinduced CT between the Fe and Cl2An ions induces a sensitive change in the state associated with the valence instability from a single‐chain, electron‐correlated state to a new photoinduced, structurally modulated state. In the photoinduced state, two absorption bands are observed, one on the higher‐energy side of the CT band and the other in the mid‐IR range. This strongly implies that the local inversion center on the Cl2An ion that exists in the initial state disappears instantly upon photoexcitation, causing an ultrafast change in the lattice structure due to the softening of rigid bonds. This has never been realized in thermal excitation. These findings demonstrate that a new electronic state with a unique lattice structure—i.e., a photoinduced hidden state—appears in this MOF system at ultra‐high speed (within 110 fs) upon photoexcitation at RT.

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Ionic-to-neutral phase transformation induced by photoexcitation of the charge-transfer band in tetrathiafulvalene-p-chloranil crystals

Cited by 72 publications

References 10 publications

Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Conceptual design of nanostructures for efficient photoinduced phase transitions

Appearance of a Photoinduced Hidden State in the Electron Donor–Acceptor Type Metal–Organic Framework (NPr₄)₂[Fe₂(Cl₂An)₃]

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Ionic-to-neutral phase transformation induced by photoexcitation of the charge-transfer band in tetrathiafulvalene-p-chloranil crystals

Cited by 72 publications

References 10 publications

Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Infrared Investigations of the Neutral-Ionic Phase Transition in TTF-CA and Its Dynamics

Conceptual design of nanostructures for efficient photoinduced phase transitions

Appearance of a Photoinduced Hidden State in the Electron Donor–Acceptor Type Metal–Organic Framework (NPr4)2[Fe2(Cl2An)3]

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Product

Resources

About

Appearance of a Photoinduced Hidden State in the Electron Donor–Acceptor Type Metal–Organic Framework (NPr₄)₂[Fe₂(Cl₂An)₃]