Ultrafast Optical Switching to a Metallic State by Photoinduced Mott Transition in a Halogen-Bridged Nickel-Chain Compound

Iwai, Shinichiro; Ono, Masashi; Maeda, Atsushi; Matsuzaki, Hiroyuki; Kishida, Hideo; Okamoto, Hiroshi; Tokura, Y.

doi:10.1103/physrevlett.91.057401

Cited by 325 publications

(303 citation statements)

References 24 publications

Supporting

Mentioning

297

Contrasting

Order By: Relevance

“…One manifestation of strong correlations, in equilibrium, is the Mott insulator, where the large cost in energy of putting two electrons on the same site leads to a charge excitation gap and inhibits conduction. Using an intense laser pulse, one can excite electrons across the charge gap, which drives the system into a nonequilibrium but relatively longlived conducting state (Ogasawara et al, 2000;Iwai et al, 2003;Perfetti et al, 2006;. Such a process, sometimes called photodoping (Nasu, 2004), is a typical example of a pathway to new phases, where mobile carriers are introduced in situ, as distinct from techniques employed in equilibrium, where the carrier concentration is typically controlled by chemical doping (Imada, Fujimori, and Tokura, 1998).…”

Section: B Physical Backgroundmentioning

confidence: 99%

“…correlated Mott and charge-transfer insulators (Ogasawara et al, 2000;Iwai et al, 2003;Perfetti et al, 2006;Kübler et al, 2007;Okamoto et al, , 2008, the pump-induced melting and recovery of charge density waves (Schmitt et al, 2008;Hellmann et al, 2010;Petersen et al, 2011) with studies combining structural and electronic dynamics (Eichberger et al, 2010), and ultrafast dynamics induced in ferromagnets (Beaurepaire et al, 1996) or antiferromagnets (Ehrke et al, 2011), to name only a few.…”

Section: B Physical Backgroundmentioning

confidence: 99%

“…Figure 3 shows an obvious parallel between condensedmatter and cold-atom systems. The top panel plots the number of excited carriers in a Mott insulator as a function of time after photoexcitation (Iwai et al, 2003), while the bottom panel plots the relaxation of the double occupancy, i.e., the probability that a single site is occupied by two fermions with opposite (hyperfine)spins, generated by a periodic modulation of the optical lattice . Doubly occupied sites play the role of carriers in a Mott insulating background, so that the two panels plot essentially the same quantity.…”

Section: B Physical Backgroundmentioning

confidence: 99%

“…For the excitation one mainly uses (i) mid-IR pulses (≈10-100 THz), which can control the properties of complex materials by selectively addressing certain optical phonons (Rini et al, 2007;Fausti et al, 2011); (ii) terahertz pulses, which act like static fields on the electron time scale (Hirori, Doi et al, 2011;Watanabe, Minami, and Shimano, 2011;Liu and , 2012); and (iii) pulses in the eV photon-energy range, which can promptly generate electron and holelike carriers (photodoping) (Iwai et al, 2003). Photodoping in correlated materials can induce, e.g., metal-insulator transitions in Mott and charge-transfer insulators, and ultrafast melting of charge and spin order (see the Introduction).…”

Section: Photoexcitations and Photodopingmentioning

confidence: 99%

See 3 more Smart Citations

Nonequilibrium dynamical mean-field theory and its applications

et al. 2014

View full text Add to dashboard Cite

The study of nonequilibrium phenomena in correlated lattice systems has developed into one of the most active and exciting branches of condensed matter physics. This research field provides rich new insights that could not be obtained from the study of equilibrium situations, and the theoretical understanding of the physics often requires the development of new concepts and methods. On the experimental side, ultrafast pump-probe spectroscopies enable studies of excitation and relaxation phenomena in correlated electron systems, while ultracold atoms in optical lattices provide a new way to control and measure the time evolution of interacting lattice systems with a vastly different characteristic time scale compared to electron systems. A theoretical description of these phenomena is challenging because, first, the quantum-mechanical time evolution of many-body systems out of equilibrium must be computed and second, strong-correlation effects which can be of a nonperturbative nature must be addressed. This review discusses the nonequilibrium extension of the dynamical mean field theory (DMFT), which treats quantum fluctuations in the time domain and works directly in the thermodynamic limit. The method reduces the complexity of the calculation via a mapping to a selfconsistent impurity problem, which becomes exact in infinite dimensions. Particular emphasis is placed on a detailed derivation of the formalism, and on a discussion of numerical techniques, which enable solutions of the effective nonequilibrium DMFT impurity problem. Insights gained into the properties of the infinite-dimensional Hubbard model under strong nonequilibrium conditions are summarized. These examples illustrate the current ability of the theoretical framework to reproduce and understand fundamental nonequilibrium phenomena, such as the dielectric breakdown of Mott insulators, photodoping, and collapse-and-revival oscillations in quenched systems. Furthermore, remarkable novel phenomena have been predicted by the nonequilibrium DMFT simulations of correlated lattice systems, including dynamical phase transitions and field-induced repulsion-to-attraction conversions.

show abstract

Section: B Physical Backgroundmentioning

confidence: 99%

Section: B Physical Backgroundmentioning

confidence: 99%

Section: B Physical Backgroundmentioning

confidence: 99%

Section: Photoexcitations and Photodopingmentioning

confidence: 99%

See 2 more Smart Citations

Nonequilibrium dynamical mean-field theory and its applications

et al. 2014

View full text Add to dashboard Cite

show abstract

“…In that respect, the recent theoretical prediction that a simple electric field could drive an insulator to metal transition in a Mott Insulator [3,4,5] appears as particularly appealing. It paves the way for a new type of RRAM based on an Electronic Phase Change, namely a Mott insulator-metal transition with a very fast potential switching time [9] .…”

mentioning

confidence: 99%

Electric‐Field‐Induced Resistive Switching in a Family of Mott Insulators: Towards a New Class of RRAM Memories

Cario¹,

Vaju²,

Corraze³

et al. 2010

Advanced Materials

135

145

View full text Add to dashboard Cite

[ # ] these authors contributes equally to this work Keywords: resistive switching, non-volatile memory, Mott insulator, metal-insulator transitionThe fundamental building blocks of modern silicon-based microelectronics, such as double gate transistors in non-volatile Flash memories, are based on the control of electrical resistance by electrostatic charging. Flash memories could soon reach their miniaturization limits mostly because reliably keeping enough electrons in an always smaller cell size will become increasingly difficult [1] . The control of electrical resistance at the nanometer scale therefore requires new concepts, and the ultimate resistance-change device is believed to exploit a purely electronic phase change such as the Mott insulator to insulator transition [ 2 ].Here we show that application of short electric pulses allows to switch back and forth between an initial high-resistance insulating state ("0" state) and a low-resistance "metallic" state ("1" state) in the whole class of Mott Insulator compounds AM 4 X 8 (A = Ga, Ge; M= V, Nb, Ta; X = S, Se). We found that electric fields as low as 2 kV/cm induce an electronic phase change in these compounds from a Mott insulating state to a metallic-like state. Our results suggest that this transition belongs to a new class of resistive switching and might be explained by recent theoretical works predicting that an insulator to metal transition can be achieved by a simple electric field in a Mott Insulator [3,4,5] . This new type of resistive switching has potential to build up a new class of Resistive Random Access Memory (RRAM) with fast writing/erasing times (50 ns to 10 µs) and resistance ratios R/R of the order of 25% at room temperature.

show abstract

Ultrafast Optical Switching by using Nanocrystals of a Halogen‐Bridged Nickel‐Chain Compound Dispersed in an Optical Polymer

et al. 2007

Self Cite

View full text Add to dashboard Cite

As the development of optical communication networks progresses, the demand for ultrafast optical switching with terahertz operation is rising. Nonlinear optical (NLO) materials with large third-order nonlinear susceptibility v (3) [1] and a small relaxation time t 1 of the photoexcited states are indispensable to these devices. Recently, it has been reported that 1D Mott insulators of halogen-bridged Ni-chain compounds exhibit large v (3) [2] and small t 1 . [3] For the application of these Ni compounds to ultrafast optical switching devices using, for example, optical waveguides, fabrication of a thin film is a most important issue. Here, we report a method for the fabrication of high-quality thin films, in which nanocrystals of a Ni compound with alkyl chains are dispersed in an optical polymer, PMMA (poly(methyl methacrylate)). In these films, terahertz repetition of optical switching by two-photon absorption (TPA) processes is demonstrated. The present approach represents a new strategy for the application of transitionmetal compounds to optical switching devices. Figure 1a shows the crystal structure of [Ni(chxn) 2 Br]Br 2 (chxn=cyclohexanediamine), [4] which is representative of the halogen-bridged Ni-chain compounds. In this compound, the Ni 3+ and Br -ions are arranged alternately along the b-axis.Four N atoms of the amino groups in two chxn molecules coordinate a Ni 3+ ion in a plane normal to b and produce a strong ligand field, so that the Ni 3+ ion is in a low-spin state and an unpaired electron exists in the d z 2 orbital. The d z 2 orbitals of Ni 3+ and the p z orbitals of Br -form a purely 1D electronic state. Due to the large electron-electron Coulomb repulsion (U) on the Ni site, a Mott-Hubbard gap is opened in the Ni 3d-band. As shown in Figure 1f, the occupied Br p-band is located between the Ni 3d upper-Hubbard (UH) band and the lower-Hubbard (LH) band, so that the chargetransfer (CT) transition from Br to Ni corresponds to the optical gap.[5]Previous electroreflectance (ER) and third-harmonic generation (THG) spectroscopic studies have revealed that [Ni(chxn) 2 Br]Br 2 shows the largest v (3) among 1D semiconductors; the maximum values of Imv(-x;0,0,x) and v (3) (-3 x;x,x,x) were 9 × 10 -5 esu (1 esu = 3.335641 × 10 -10 C) and 4 × 10 -8 esu, respectively. [2,6,7] These measurements were performed on single crystals (Fig. 1c) because the fabrication of film samples has not been successful, owing to the low solubility in organic solvents as well as the difficulty of vapor deposition. One way of fabricating an optical thin film in such cases is to disperse nanocrystals in optically transparent polymers. This method has been employed for the fabrication of good optical films of single-wall carbon nanotubes, using gelatin, polyvinyl alcohol, and carboxymethylcellulose as matrices.[8-10] Before we can apply this method to a Ni compound, its affinity to organic solvents should be improved. An effective method for this is to introduce alkyl chains. Indeed, in halogen-bridged mixed-valence plati...

show abstract

Ultrafast Optical Switching to a Metallic State by Photoinduced Mott Transition in a Halogen-Bridged Nickel-Chain Compound

Cited by 325 publications

References 24 publications

Nonequilibrium dynamical mean-field theory and its applications

Nonequilibrium dynamical mean-field theory and its applications

Electric‐Field‐Induced Resistive Switching in a Family of Mott Insulators: Towards a New Class of RRAM Memories

Ultrafast Optical Switching by using Nanocrystals of a Halogen‐Bridged Nickel‐Chain Compound Dispersed in an Optical Polymer

Contact Info

Product

Resources

About