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Lantz, Gabriel; Hajlaoui, Mahdi; Papalazarou, E.; Jacques, Vincent; Mazzotti, A.; Marsi, M.; Lupi, S.; Amati, Matteo; Gregoratti, Luca; Si, Liang; Zhong, Zhicheng; Held, Karsten

doi:10.1103/physrevlett.115.236802

Cited by 19 publications

(17 citation statements)

References 55 publications

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“…However, the correlation length stays larger than during the growth. We suggest that the large domains and the domains with defects are more stable and therefore the intensity drop is mostly due to the disappearance of the small domains, which are less stable [26,27].…”

Section: Discussionmentioning

confidence: 88%

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

et al. 2017

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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.

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Section: Discussionmentioning

confidence: 88%

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

et al. 2017

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“…In both cases, this state is stabilized by a transient lattice deformation that shortens the distance between the two nearest vanadium atoms and consequently increases the covalent bonding between the a 1 g orbitals. The fact that trXRD gives a slightly longer relaxation time with respect to trPES can be explained by the different probing depths of the two techniques636.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast evolution and transient phases of a prototype out-of-equilibrium Mott–Hubbard material

et al. 2017

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The study of photoexcited strongly correlated materials is attracting growing interest since their rich phase diagram often translates into an equally rich out-of-equilibrium behaviour. With femtosecond optical pulses, electronic and lattice degrees of freedom can be transiently decoupled, giving the opportunity of stabilizing new states inaccessible by quasi-adiabatic pathways. Here we show that the prototype Mott–Hubbard material V2O3 presents a transient non-thermal phase developing immediately after ultrafast photoexcitation and lasting few picoseconds. For both the insulating and the metallic phase, the formation of the transient configuration is triggered by the excitation of electrons into the bonding a1g orbital, and is then stabilized by a lattice distortion characterized by a hardening of the A1g coherent phonon, in stark contrast with the softening observed upon heating. Our results show the importance of selective electron–lattice interplay for the ultrafast control of material parameters, and are relevant for the optical manipulation of strongly correlated systems.

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“…Thanks to its advantageous combination of surface sensitivity, energy resolution, and spatial resolution, SPEM is an ideal method to probe the surface microscopic structure of this phase coexistence at the Mott transition . In Figure b we present the spectroscopic contrast between the photoemission signal from the metallic phase (red) and the insulating phase (blue), which in imaging mode make it possible to discriminate metallic (red) from insulating (blue) areas at the surface of the material (Figure a).…”

Section: Resultsmentioning

confidence: 99%

“…Phase coexistence and domain formation are naturally expected for all first order transitions: for instance, near‐field optical microscopy is also able to identify them in undoped V 2 O 3 for the transition between the low temperature antiferromagnetic insulating phase and the high temperature metallic phase . With SPEM it has been possible to study the real, isostructural Mott transition in (V 1‐x Cr x ) 2 O 3 ( x = 0.011), and demonstrate that various effects (surface reconstruction, surface crystallographic orientation) contribute to determine the position, size, and shape of the domains . In particular, it has been possible to show that surface defects act as nucleation centers for the formation of domains; thanks to advanced theoretical modeling, it is also possible to show how certain surface terminations favor the formation of metallic islands.…”

Section: Resultsmentioning

confidence: 99%

Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the Nanoscale

Zeller

Amati

Sezen

et al. 2018

Physica Status Solidi (a)

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The advanced properties of modern materials originate from their nanoscale size and shape and from chemical modifications or doping. Special techniques that can measure the chemical state in the nanoscale are required for exploration and understanding the properties of these materials. While X‐ray photoelectron spectroscopy (XPS) can access the necessary chemical information, conventional setups have no spatial resolution. The scanning photoelectron microscope (SPEM) takes in advent the third generation synchrotron radiation facilities and uses a zone plate (ZP) focusing optics that allows spatially resolved XPS measurements in the submicron scale. Several recent examples of investigations of chemically modified or doped nanomaterials are given. The modification of suspended and supported graphene with nitrogen and fluorine is presented as well as the doping dependent position of the Fermi‐level in single GsAs nanowires and the Mott–Hubbard transition in Cr‐doped vanadium oxide. These examples show several peculiar SPEM abilities like a high surface and chemical sensitivity and a submicron spatial resolution proving the capability and importance of this technique to study materials at the nanoscale.

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Surface Effects on the Mott-Hubbard Transition in ArchetypalV2O3

Cited by 19 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

Ultrafast evolution and transient phases of a prototype out-of-equilibrium Mott–Hubbard material

Scanning Photoelectron Spectro‐Microscopy: A Modern Tool for the Study of Materials at the Nanoscale

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