Phase coexistence and pinning of charge density waves by interfaces in chromium

Singer, Andrej; Patel, Sheena K. K.; Uhlíř, Vojtěch; Kukreja, Roopali; Ulvestad, Andrew; Đufresne, Eric M.; Sandy, Alec; Fullerton, Eric E.; Shpyrko, Oleg

doi:10.1103/physrevb.94.174110

Cited by 8 publications

(8 citation statements)

References 26 publications

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“…This is also consistent with the observed decrease in correlation lengths of orbitally-ordered domains from 17 nm to 6 nm with a normalized integrated peak intensity drop of 80% to 10% near 100 K. In this phase separation regime, the metallic/insulating interface leads to the pinning of the trimeron chains, resulting in a slowdown of orbital fluctuation timescales. Pinning of charge density waves by an interface has been previously observed in other correlated systems [24].…”

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confidence: 52%

Orbital Domain Dynamics in Magnetite below the Verwey Transition

et al. 2018

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The metal-insulator phase transition in magnetite, known as the Verwey transition, is characterized by a charge-orbital ordering and a lattice transformation from a cubic to monoclinic structure. We use x-ray photon correlation spectroscopy to investigate the dynamics of this charge-orbitally ordered insulating phase undergoing the insulator-tometal transition. By tuning to the Fe L 3-edge at the (00 " #) superlattice peak, we probe the evolution of the Fe t 2g orbitally-ordered domains present in the low temperature insulating phase and forbidden in the high temperature metallic phase. We observe two distinct regimes below the Verwey transition. In the first regime, magnetite follows an Arrhenius behavior and the characteristic timescale for orbital fluctuations decreases as the temperature increases. In the second regime, magnetite phase separates into metallic and insulating domains, and the kinetics of the phase transition is dictated by metallicinsulating interfacial boundary conditions. Mesoscale phenomena play an important role in the dynamics of phase transitions in strongly-correlated electron systems. In addition to the coupling of charge, spin, orbital and lattice degrees of freedom, the underlying mechanism of phase transformations is influenced by nanoscale heterogeneities such as local strain fields, phase separation,

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confidence: 52%

Orbital Domain Dynamics in Magnetite below the Verwey Transition

et al. 2018

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“…In comparison to our previous study of the same sample at cryogenic temperatures [13], the CDW observed here at room temperature has a lower spatial frequency and reduced amplitude, which are shifted by an amount consistent with previous studies [24]. We want to stress that previous works by Singer et al studied this same Cr sample [13,25,26], focusing exclusively on the CDW, and for that reason we do not include a more in-depth discussion of this mechanism here.…”

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confidence: 91%

“…The amplitudes can be fit well with a Gaussian (as used to model the Laue fringe envelope from surface roughness in Ref. [26]) summed with a Lorentzian for the CDW (a Gaussian CDW peak gives a slightly lower quality fit). An important feature of the data is the reduced amplitude of the oscillations that occurs after about 4 ps (see Fig.…”

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confidence: 99%

Direct time-domain determination of electron-phonon coupling strengths in chromium

et al. 2020

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“…The high Néel temperatures (311 K in bulk 3 , decreased due to dimensional crossover 10 to 290 ± 5 K in the 28 nm film studied here 11 , 12 ) render the critical behaviour close to the SDW phase transition highly accessible. Thin antiferromagnetic films with SDW states are especially important for devices utilizing spin transport 13 , 14 and sustain a unidirectional SDW and discrete SDW periods due to pinning at the interfaces 15 , 16 . The magnetostrictive coupling between SDW and PLD allows for the excitation of acoustic phonons by fully or partially quenching the SDW order parameter throughout the film with a photoexcitation 17 – 19 .…”

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confidence: 99%

Femtosecond control of phonon dynamics near a magnetic order critical point

et al. 2021

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The spin-phonon interaction in spin density wave (SDW) systems often determines the free energy landscape that drives the evolution of the system. When a passing energy flux, such as photoexcitation, drives a crystalline system far from equilibrium, the resulting lattice displacement generates transient vibrational states. Manipulating intermediate vibrational states in the vicinity of the critical point, where the SDW order parameter changes dramatically, would then allow dynamical control over functional properties. Here we combine double photoexcitation with an X-ray free-electron laser (XFEL) probe to control and detect the lifetime and magnitude of the intermediate vibrational state near the critical point of the SDW in chromium. We apply Landau theory to identify the mechanism of control as a repeated partial quench and sub picosecond recovery of the SDW. Our results showcase the capabilities to influence and monitor quantum states by combining multiple optical photoexcitations with an XFEL probe. They open new avenues for manipulating and researching the behaviour of photoexcited states in charge and spin order systems near the critical point.

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Phase coexistence and pinning of charge density waves by interfaces in chromium

Cited by 8 publications

References 26 publications

Orbital Domain Dynamics in Magnetite below the Verwey Transition

Orbital Domain Dynamics in Magnetite below the Verwey Transition

Direct time-domain determination of electron-phonon coupling strengths in chromium

Femtosecond control of phonon dynamics near a magnetic order critical point

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