Phonon dynamics in CuxBi2Se3 (x = 0, 0.1, 0.125) and Bi2Se2 crystals studied using femtosecond spectroscopy

Chen, H. J.; Wu, Kaung‐Hsiung; Luo, Chih-Wei; Uen, T. M.; Juang, Jenh‐Yih; Lin, Jiunn-Yuan; Kobayashi, Takayoshi; Yang, H. D.; Sankar, Raman; Chou, F. C.; Berger, H.; Liu, J. M.

doi:10.1063/1.4754005

Cited by 36 publications

(58 citation statements)

References 31 publications

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“…However, with higher Cu concentration, of x=0.3 and x=0.5, we observe a hardening of the A g 1 2 and E g 2 phonon modes, together with a broadening of the peak widths. Previous reports have ascribed similar softening versus hardening of A 1g and E g modes to intercalation and substitution [32,33]. Chen et al [33] conclude that the A g 1 1 mode in Bi 2 Se 3 shifts to lower frequency with increasing Cu intercalation.…”

Section: Raman Spectroscopymentioning

confidence: 76%

“…Previous reports have ascribed similar softening versus hardening of A 1g and E g modes to intercalation and substitution [32,33]. Chen et al [33] conclude that the A g 1 1 mode in Bi 2 Se 3 shifts to lower frequency with increasing Cu intercalation. In contrast, substitution of lighter atoms at the Bi site has been found to result in A , g 1 1 A , g 1 2 E g 1 and E g 2 modes shifting to higher frequency [17,32].…”

Section: Raman Spectroscopymentioning

confidence: 76%

“…We could try to understand this as follows. When Cu enters as an intercalant between two quintuple layers (QL), each QL experiences an extra Coulomb force resulting from the Cu in the van der Waals spaces [4,9,33]. This Coulomb interaction can modify bond-lengths and structure of the QL, thus affecting the phonon vibrational frequency.…”

Section: Raman Spectroscopymentioning

confidence: 99%

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Possible lattice and charge order in Cu_xBi₂Te₂Se

Smith

Rexhausen

et al. 2019

J. Phys. Mater.

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Metal intercalation into layered topological insulator materials such as the binary chalcogenide Bi 2 X 3 (X=Te or Se) has yielded novel two-dimensional (2D) electron-gas physics, phase transitions to superconductivity, as well as interesting magnetic ground states. Of recent interest is the intercalationdriven interplay between lattice distortions, density wave ordering, and the emergence of new phenomena in the vicinity of instabilities induced by intercalation. Here, we examine the effects of Cu-intercalation on the ternary chalcogenide Bi 2 Te 2 Se. We report the discovery, in Cu 0.3 Bi 2 Te 2 Se, of a periodic lattice distortion (PLD) at room temperature, together with a charge density wave (CDW) transition around T d =220 K. We also report, for the first time, a complete study of the Cu x Bi 2 Te 2 Se system, and the effect of Cu-intercalation on crystal structure, phonon structure, and electronic properties for 0.0x0.5. Our electron diffraction studies reveal strong Bragg spots at reciprocal lattice positions forbidden by ABC stacking, possibly resulting from stacking faults, or a superlattice. The c-axis lattice parameter varies monotonically with x for 0<x<0.2, but drops precipitously for higher x. Similarly, Raman phonon modes A g 1 2 and E g 2 soften monotonically for 0<x<0.2 but harden sharply for x>0.2. This indicates that Cu likely intercalates up to x∼0.2, followed by partial site-substitutions at higher values. The resulting strain makes the 0.2x0.3 region susceptible to instabilities and distortions. Our results point toward the presence of an incommensurate CDW above T d =220 K. This work strengthens prevalent thought that intercalation contributes significantly to instabilities in the lattice and charge degrees of freedom in layered chalcogenides. Further work is required to uncover additional density wave transitions, and possible ground states such as superconductivity.

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Section: Raman Spectroscopymentioning

confidence: 76%

Section: Raman Spectroscopymentioning

confidence: 76%

Section: Raman Spectroscopymentioning

confidence: 99%

See 1 more Smart Citation

Possible lattice and charge order in Cu_xBi₂Te₂Se

Smith

Rexhausen

et al. 2019

J. Phys. Mater.

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“…High time-resolution TR-reflectivity has been widely employed for studying photoinduced phonons. In particular, A 1g phonons with a frequency of a few THz have been commonly observed in TIs after a near-IR perturbation [45][46][47][48][49][50][51]. To confirm the presence of lattice vibrations photoinduced by the pump, we have thus performed a high time-resolution TR-reflectivity investigation of BSTS, which is so far missing to the best of our knowledge.…”

Section: Resultsmentioning

confidence: 99%

Role of matrix elements in the time-resolved photoemission signal

et al. 2020

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Time-and angle-resolved photoemission spectroscopy (TR-ARPES) provides access to the ultrafast evolution of electrons and many-body interactions in solid-state systems. However, the momentum-and energy-resolved transient photoemission intensity may not be unambiguously described by the intrinsic relaxation dynamics of photoexcited electrons alone. The interpretation of the time-dependent photoemission signal can be affected by the transient evolution of the electronic distribution, and both the one-electron removal spectral function as well as the photoemission matrix elements. Here we investigate the topological insulator Bi 1.1 Sb 0.9 Te 2 S to demonstrate, by means of a detailed probe-polarization dependent study, the transient contribution of matrix elements to TR-ARPES.

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“…These kinds of femtosecond laser pulses are widely used in research in physics, materials science, chemistry, biology, and bioengineering. For example, laser plasma physics [17,18], ultrafast reaction dynamics in chemistry, biomacromolecules [19,20], solid-state [21][22][23][24], and two-photon laser microscopy [25][26][27] require femtosecond pulses as a laser excitation source. Pulse duration or the complete temporal profile of a femtosecond pulse is a very important parameter in applications of the above-mentioned fields, because it is indicative of not only the speed but also the peak power of the pulse.…”

Section: Introductionmentioning

confidence: 99%

Self-Referenced Spectral Interferometry for Femtosecond Pulse Characterization

et al. 2017

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Abstract:Since its introduction in 2010, self-referenced spectral interferometry (SRSI) has turned out to be an analytical, sensitive, accurate, and fast method for characterizing the temporal profile of femtosecond pulses. We review the underlying principle and the recent progress in the field of SRSI. We present our experimental work on this method, including the development of self-diffraction (SD) effect-based SRSI (SD-SRSI) and transient-grating (TG) effect-based SRSI (TG-SRSI). Three experiments based on TG-SRSI were performed: (1) We built a simple TG-SRSI device and used it to characterize a sub-10 fs pulse with a center wavelength of 1.8 µm. (2) On the basis of the TG effect, we successfully combined SRSI and frequency-resolved optical gating (FROG) into a single device. The device has a broad range of application, because it has the advantages of both SRSI and FROG methods. (3) Weak sub-nanojoule pulses from an oscillator were successfully characterized using the TG-SRSI device, the optical setup of which is smaller than the palm of a hand, making it convenient for use in many applications, including sensor monitoring the pulse profile of laser systems. In addition, the SRSI method was extended for single-shot characterization of the temporal contrast of ultraintense and ultrashort laser pulses.

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Phonon dynamics in Cu_xBi₂Se₃ (x = 0, 0.1, 0.125) and Bi₂Se₂ crystals studied using femtosecond spectroscopy

Cited by 36 publications

References 31 publications

Possible lattice and charge order in Cu_xBi₂Te₂Se

Possible lattice and charge order in Cu_xBi₂Te₂Se

Role of matrix elements in the time-resolved photoemission signal

Self-Referenced Spectral Interferometry for Femtosecond Pulse Characterization

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Phonon dynamics in CuxBi2Se3 (x = 0, 0.1, 0.125) and Bi2Se2 crystals studied using femtosecond spectroscopy

Cited by 36 publications

References 31 publications

Possible lattice and charge order in CuxBi2Te2Se

Possible lattice and charge order in CuxBi2Te2Se

Role of matrix elements in the time-resolved photoemission signal

Self-Referenced Spectral Interferometry for Femtosecond Pulse Characterization

Contact Info

Product

Resources

About

Phonon dynamics in Cu_xBi₂Se₃ (x = 0, 0.1, 0.125) and Bi₂Se₂ crystals studied using femtosecond spectroscopy

Possible lattice and charge order in Cu_xBi₂Te₂Se

Possible lattice and charge order in Cu_xBi₂Te₂Se