Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography

Han, Tzong Ru T; Zhou, Faran; Malliakas, Christos D.; Duxbury, Phillip M.; Mahanti, S. D.; Kanatzidis, Mercouri G.; Ruan, Chong‐Yu

doi:10.1126/sciadv.1400173

Cited by 116 publications

(123 citation statements)

References 55 publications

Supporting

Mentioning

111

Contrasting

Order By: Relevance

“…The most significant difference between the two experiments is the photon energy of the pump, which is two times larger for the present experiment. The time-resolved electron diffraction work of Han et al [8] showed very different threshold behavior for photoinduced phase transitions starting from the C-CDW phase for 800 nm versus 2500 nm pumping wavelengths, even after correcting for differences in absorption. This suggests that the occurrence of the photoinduced phase transitions does not depend on the overall absorbed energy density.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

et al. 2017

View full text Add to dashboard Cite

Recent experiments have shown that the high temperature incommensurate (I) charge density wave (CDW) phase of 1T-TaS2 can be photoinduced from the lower temperature, nearly commensurate (NC) CDW state. Here we report a time-resolved x-ray diffraction study of the growth process of the photoinduced I-CDW domains. The layered nature of the material results in a marked anisotropy in the size of the photoinduced domains of the I-phase. These are found to grow self-similarly, their shape remaining unchanged throughout the growth process. The photoinduced dynamics of the newly formed I-CDW phase was probed at various stages of the growth process using a double pump scheme, where a first pump creates I-CDW domains and a second pump excites the newly formed I-CDW state. We observe larger magnitudes of the coherently excited I-CDW amplitude mode in smaller domains, which suggests that the incommensurate lattice distortion is less stable for smaller domain sizes.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Below 180 K, these discommensuration regions disappear and the material becomes insulating, forming the commensurate (C) phase. Femtosecond laser excitation has been shown to trigger transitions from the C and NC phases to the NC and I phases, respectively [8,9]. The photoinduced NC to I transition is the focus of the present work.…”

Section: Introductionmentioning

confidence: 96%

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

et al. 2017

View full text Add to dashboard Cite

show abstract

“…In this strongly nonequilibrium condition, the thermodynamic ground state may become less stable than its counterparts and metastable new phases may emerge34. Characterizing the nonequilibrium transformations between two thermodynamic phases directly or through a metastable phase indirectly may provide valuable insights regarding the nature of these states, the interactions, and the active coordinates involved in these phase transitions5.…”

mentioning

confidence: 99%

The nature of photoinduced phase transition and metastable states in vanadium dioxide

Tao

Zhou

Han

et al. 2016

Sci Rep

Self Cite

View full text Add to dashboard Cite

Photoinduced threshold switching processes that lead to bistability and the formation of metastable phases in photoinduced phase transition of VO2 are elucidated through ultrafast electron diffraction and diffusive scattering techniques with varying excitation wavelengths. We uncover two distinct regimes of the dynamical phase change: a nearly instantaneous crossover into an intermediate state and its decay led by lattice instabilities over 10 ps timescales. The structure of this intermediate state is identified to be monoclinic, but more akin to M2 rather than M1 based on structure refinements. The extinction of all major monoclinic features within just a few picoseconds at the above-threshold-level (~20%) photoexcitations and the distinct dynamics in diffusive scattering that represents medium-range atomic fluctuations at two photon wavelengths strongly suggest a density-driven and nonthermal pathway for the initial process of the photoinduced phase transition. These results highlight the critical roles of electron correlations and lattice instabilities in driving and controlling phase transformations far from equilibrium.

show abstract

“…The electron pumping mechanism across a structural phase transition that we observe for Cu 2 S nanoplates will no doubt also be operating in other metastable and nonequilibrium phases as well, and for metal-insulator phase transitions in general in nanoparticles of complex materials (26)(27)(28).…”

Section: Significancementioning

confidence: 99%

Reversible structure manipulation by tuning carrier concentration in metastable Cu ₂ S

Tao

Chen

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

The optimal functionalities of materials often appear at phase transitions involving simultaneous changes in the electronic structure and the symmetry of the underlying lattice. It is experimentally challenging to disentangle which of the two effects--electronic or structural--is the driving force for the phase transition and to use the mechanism to control material properties. Here we report the concurrent pumping and probing of Cu 2 S nanoplates using an electron beam to directly manipulate the transition between two phases with distinctly different crystal symmetries and charge-carrier concentrations, and show that the transition is the result of charge generation for one phase and charge depletion for the other. We demonstrate that this manipulation is fully reversible and nonthermal in nature. Our observations reveal a phase-transition pathway in materials, where electron-induced changes in the electronic structure can lead to a macroscopic reconstruction of the crystal structure. functional and quantum materials--the key properties of functional materials are often born out of strong structural and electronic interactions that are quantum mechanical in nature. Notable examples include colossal magnetoresistance manganites (1), ferroelectrics (2), and valleytronic materials (3). The targeted functions are usually accompanied by symmetry breaking, induced through changes in temperature or under other external perturbations. A prominent question is whether the symmetry reduction has an origin in the lattice (e.g., in the form of displacement of atoms, and could be described reasonably well using first-principles calculations) or the electronic degrees of freedom (charge, spin, and orbital) (4-6). It is of great interest to distinguish the roles of these factors in phase transitions.Cu 2 S provides an intriguing example for addressing the above "chicken-and-egg" question (6), which is critical to the understanding of a wide range of functional and quantum materials. It is a fast ionic conductor (7) with highly mobile Cu ions. A phase transition in the bulk material occurs near 100°C from a semiconducting (8) monoclinic symmetry low-chalcocite phase (9) [hereafter called the "L-s phase" (i.e., low, semiconducting); space group P2 1 /c] to an electrically insulating (10) hexagonal symmetry high-chalcocite phase (7, 11) [hereafter called the "H-i phase" (i.e., high, insulating); space group P6 3 /mmc]. The coinciding changes in the bulk electrical conductivity and crystal structure present a possibility for exploring the relationship between electronic and structural phase transitions. Difficulties in the synthesis of stoichiometric Cu 2 S material and the lack of detailed theoretical treatments of both the crystal and the electronic structures of Cu 2 S have hindered the understanding of the phase transition (7, 11-13). Results and DiscussionWe have recently synthesized high-quality Cu 2 S nanoplates (Materials and Methods), which are on the order of 10-nm thick and 100 nm in lateral dimension ( Fig. 1 A and B)....

show abstract

Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography

Abstract: Using femtosecond photodoping and crystallography to explore metastable and hidden quantum phases in tantalum disulfide.

Cited by 116 publications

References 55 publications

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

The nature of photoinduced phase transition and metastable states in vanadium dioxide

Reversible structure manipulation by tuning carrier concentration in metastable Cu ₂ S

Contact Info

Product

Resources

About

Exploration of metastability and hidden phases in correlated electron crystals visualized by femtosecond optical doping and electron crystallography

Abstract: Using femtosecond photodoping and crystallography to explore metastable and hidden quantum phases in tantalum disulfide.

Cited by 116 publications

References 55 publications

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

Domain-size effects on the dynamics of a charge density wave in 1T−TaS2

The nature of photoinduced phase transition and metastable states in vanadium dioxide

Reversible structure manipulation by tuning carrier concentration in metastable Cu 2 S

Contact Info

Product

Resources

About

Reversible structure manipulation by tuning carrier concentration in metastable Cu ₂ S