Transient Electronic Structure and Melting of a Charge Density Wave in TbTe
            <sub>3</sub>

Schmitt, Felix; Kirchmann, Patrick S.; Bovensiepen, Uwe; Moore, Robert; Rettig, Laurenz; Krenz, M.; Chu, J.-H.; Ru, N.; Perfetti, L.; Lü, Donghui; Wolf, Martin; Fisher, I. R.; Shen, Zhi‐Xun

doi:10.1126/science.1160778

Cited by 489 publications

(482 citation statements)

References 25 publications

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“…2a,b). This is the region in which the primary structural component of the CDW in 1T-TaS 2 can be probed, as confirmed by the vibrational timescale of the spectral response and consistent with the delayed response seen in paradigmatic CDW systems 35,50 . In a recent time-resolved ARPES study of 1T-TaS 2 (ref.…”

Section: Discussionsupporting

confidence: 68%

“…We now set out to answer these questions by time-resolved pump-probe ARPES [16][17][18][19]35,36 using a highharmonic-generation source 37,38 . The central idea is that the timescale on which electronic order in momentum space melts should provide a strong hint as to its predominant nature or origin.…”

Section: Systemsmentioning

confidence: 99%

“…However, what is important for the following quantitative analysis is that the experimentally determined values of τ amp (or some fraction thereof) define an intrinsic timescale for the fastest possible structural response in the two systems 16,17,35,36,40 . Figure 5 shows characteristic ARPES intensity transients, extracted from the data in Fig.…”

Section: Systemsmentioning

confidence: 99%

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Time-domain classification of charge-density-wave insulators

et al. 2012

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Distinguishing insulators by the dominant type of interaction is a central problem in condensed matter physics. Basic models include the Bloch-Wilson and the Peierls insulator due to electron-lattice interactions, the mott and the excitonic insulator caused by electron-electron interactions, and the Anderson insulator arising from electron-impurity interactions. In real materials, however, all the interactions are simultaneously present so that classification is often not straightforward. Here, we show that time-and angle-resolved photoemission spectroscopy can directly measure the melting times of electronic order parameters and thus identify-via systematic temporal discrimination of elementary electronic and structural processes-the dominant interaction. specifically, we resolve the debates about the nature of two peculiar charge-density-wave states in the family of transition-metal dichalcogenides, and show that Rb intercalated 1T-Tas 2 is a Peierls insulator and that the ultrafast response of 1T-Tise 2 is highly suggestive of an excitonic insulator.

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Section: Discussionsupporting

confidence: 68%

Section: Systemsmentioning

confidence: 99%

Section: Systemsmentioning

confidence: 99%

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Time-domain classification of charge-density-wave insulators

et al. 2012

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“…As has recently been demonstrated 15 in the topological insulator Bi 2 Se 3 , time-and angleresolved photoemission spectroscopy (Tr-ARPES) is a key tool that can achieve this. Characteristic signatures of Floquet-Bloch states in the Tr-ARPES spectra include replicas of the original band structure that are separated by the driving photon energy 15 .In addition to Floquet-Bloch states, light can also generate other coherent phenomena in solids [16][17][18] . In particular, it can dress freeelectron states near the surface of a solid (Fig.…”

mentioning

confidence: 99%

“…In addition to Floquet-Bloch states, light can also generate other coherent phenomena in solids [16][17][18] . In particular, it can dress freeelectron states near the surface of a solid (Fig.…”

mentioning

confidence: 99%

Selective scattering between Floquet–Bloch and Volkov states in a topological insulator

Mahmood¹,

Chan²,

Alpichshev³

et al. 2016

Nature Phys

320

273

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The coherent optical manipulation of solids is emerging as a promising way to engineer novel quantum states of matter 1-5 . The strong time-periodic potential of intense laser light can be used to generate hybrid photon-electron states. Interaction of light with Bloch states leads to Floquet-Bloch states, which are essential in realizing new photo-induced quantum phases [6][7][8] . Similarly, dressing of free-electron states near the surface of a solid generates Volkov states, which are used to study nonlinear optics in atoms and semiconductors 9 . The interaction of these two dynamic states with each other remains an open experimental problem. Here we use time-and angle-resolved photoemission spectroscopy (Tr-ARPES) to selectively study the transition between these two states on the surface of the topological insulator Bi 2 Se 3 . We find that the coupling between the two strongly depends on the electron momentum, providing a route to enhance or inhibit it. Moreover, by controlling the light polarization we can negate Volkov states to generate pure Floquet-Bloch states. This work establishes a systematic path for the coherent manipulation of solids via light-matter interaction.The manipulation of solids using ultrafast optical pulses has opened up a new paradigm in condensed matter physics by allowing the study of emergent physical properties that are otherwise inaccessible in equilibrium 1,2,10 . An important example is provided by the Floquet-Bloch states 11 , which emerge in solids owing to a coherent interaction between Bloch states inside the solid and a periodic driving potential. This is a consequence of the Floquet theorem 12 , which states that a Hamiltonian periodic in time with period T has eigenstates that are evenly spaced by the drive energy (2π/T ). Floquet-Bloch states have generated a lot of interest recently both for realizing exotic states of matter such as a Floquet Chern insulator 7 , as well as understanding non-equilibrium periodic thermodynamics 13,14 . Experimental observation of these states requires the measurement of the transient electronic band structure of a crystal as it is perturbed by light. As has recently been demonstrated 15 in the topological insulator Bi 2 Se 3 , time-and angleresolved photoemission spectroscopy (Tr-ARPES) is a key tool that can achieve this. Characteristic signatures of Floquet-Bloch states in the Tr-ARPES spectra include replicas of the original band structure that are separated by the driving photon energy 15 .In addition to Floquet-Bloch states, light can also generate other coherent phenomena in solids [16][17][18] . In particular, it can dress freeelectron states near the surface of a solid (Fig. 1a), as the surface can provide the momentum conservation necessary for a photon to interact with a free electron. This dressing was first observed in time-resolved photoemission experiments 17 and has subsequently been referred to as laser-assisted photoemission (LAPE). LAPE is typically understood [19][20][21] by invoking the Volkov solution, which is an e...

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Excitation and Time‐Evolution of Coherent Optical Phonons

Hase

Misochko

Ishioka

2010

Dynamics at Solid State Surfaces and Interfaces

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Coherent optical phonons are the lattice vibrations of the optical branches excited in-phase over a macroscopic spatial region by ultrashort laser pulses. Their generation and relaxation dynamics have been investigated by optical pump-probe techniques in a broad range of solid materials. When probed with a linear optical process such as reflection, the probing depth is from nanometers to micrometers determined by the absorption coefficient and the laser wavelength. By employing a nonlinear optical process such as second harmonic generation, however, it is possible to monitor coherent phonons at surfaces and interfaces exclusively. When the photoexcitation creates electron-hole plasma, coherent phonons can also serve as an ultrafast probe of nonequilibrium electron-phonon coupling. Using an optical pulse train with a designed repetition rate, coherent phonons can be excited to large amplitudes, which is expected to be a promising strategy toward nonthermal phase transitions in solids. New femtosecond beam sources such as X-ray and THz pulses offer complementary techniques to probe the ultrafast phononic and electronic dynamics under extremely nonequilibrium conditions. Coherent Phonons in Group V SemimetalsBismuth (Bi) and antimony (Sb) have been model systems for optical studies on coherent phonons because of their relatively low frequencies and large amplitudes in the optical reflectivity. They both have an A7 crystalline structure and sustain two Raman-active optical phonon modes shown in Figure 10.1e. The coherent phonons of A 1g and E g symmetries have been detected as periodic modulations of the reflectivity (Figure 10.1a) in the order of DR=R¼ 10 À6 to 10 À2 depending on the excitation density. Recently, the coherent A 1g phonons of Bi have gained a renewed interest as the benchmark for femtosecond X-ray diffraction experiments.

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Transient Electronic Structure and Melting of a Charge Density Wave in TbTe ₃

Cited by 489 publications

References 25 publications

Time-domain classification of charge-density-wave insulators

Time-domain classification of charge-density-wave insulators

Selective scattering between Floquet–Bloch and Volkov states in a topological insulator

Excitation and Time‐Evolution of Coherent Optical Phonons

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Transient Electronic Structure and Melting of a Charge Density Wave in TbTe 3

Cited by 489 publications

References 25 publications

Time-domain classification of charge-density-wave insulators

Time-domain classification of charge-density-wave insulators

Selective scattering between Floquet–Bloch and Volkov states in a topological insulator

Excitation and Time‐Evolution of Coherent Optical Phonons

Contact Info

Product

Resources

About

Transient Electronic Structure and Melting of a Charge Density Wave in TbTe ₃