Measurement of Two Low-Temperature Energy Gaps in the Electronic Structure of Antiferromagnetic<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mi>USb</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:math>Using Ultrafast Optical Spectroscopy

Qi, J.; Durakiewicz, Tomasz; Trugman, S. A.; Zhu, Jian‐Xin; Riseborough, Peter S.; Baumbach, Ryan; Bauer, E. D.; Gofryk, K.; Meng, Jianqiao; Joyce, John J.; Taylor, Antoinette J.; Prasankumar, R. P.

doi:10.1103/physrevlett.111.057402

Cited by 38 publications

(30 citation statements)

References 38 publications

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“…Although RT model is proposed to explain the bottleneck effect in a superconductor due to the opening of pairing energy gap, it is widely used to interpret similar effects of decay time increase in CDW materials (e.g. K0.3MoO3, 20 RTe3, 13 transition metal dichacogenides 21 ) or even in heavy fermion systems with the presence of hybridization energy gaps 22,23 . We use equation (2) to fit the temperature dependent amplitude and the result is shown in Figure 4 (a).…”

Section: Resultsmentioning

confidence: 99%

Revealing multiple charge-density-wave orders inTbTe3by optical conductivity and ultrafast pump-probe experiments

Chen

Dong

et al. 2014

Phys. Rev. B

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Rare-earth tri-tellurium RTe 3 is a typical quasi-two dimensional system which exhibits obvious charge density wave (CDW) orders. So far, RTe 3 with heavier R ions (Dy, Ho, Er and Tm) are believed to experience two CDW phase transitions, while the lighter ones only hold one. TbTe 3 is claimed to belong to the latter. However in this work we present evidences that TbTe 3 also possesses more than one CDW order. Aside from the one at 336 K, which was extensively studied and reported to be driven by imperfect Fermi surface nesting with a wave vector q = (2/7c * ), a new CDW energy gap (260 meV) develops at around 165 K, revealed by both infrared reflectivity spectroscopy and ultrafast pump-probe spectroscopy. More intriguingly, the origin of this energy gap is different from the second CDW order in the heavier R ions-based compounds RTe 3 (R=Dy, Ho, Er and Tm).

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Section: Resultsmentioning

confidence: 99%

Revealing multiple charge-density-wave orders inTbTe3by optical conductivity and ultrafast pump-probe experiments

Chen

Dong

et al. 2014

Phys. Rev. B

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“…Carrier relaxation depends sensitively on the band structure and scattering mechanisms in a solid [14][15][16][17], and therefore an understanding of the ultrafast carrier dynamics in WTe 2 may shed new light on the mechanism of the anomalous MR. This also directly resolves the timescales that ultimately limit potential applications of WTe 2 in electronic devices, e.g., high speed solid-state drives.…”

mentioning

confidence: 99%

Ultrafast carrier dynamics in the large magnetoresistance material WTe2

Dai

Bowlan

et al. 2016

International Conference on Ultrafast Phenomena

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Ultrafast optical pump-probe spectroscopy is used to track carrier dynamics in the large magnetoresistance material WTe2. Our experiments reveal a fast relaxation process occurring on a sub-picosecond time scale that is caused by electron-phonon thermalization, allowing us to extract the electron-phonon coupling constant. An additional slower relaxation process, occurring on a time scale of ∼5-15 picoseconds, is attributed to phonon-assisted electron-hole recombination. As the temperature decreases from 300 K, the timescale governing this process increases due to the reduction of the phonon population. However, below ∼50 K, an unusual decrease of the recombination time sets in, most likely due to a change in the electronic structure that has been linked to the large magnetoresistance observed in this material. has aroused tremendous interest, due not only to its potential application in devices such as magnetic sensors and hard drives, but also to the enigmatic nature of this effect. The observed MR in Cd 3 As 2 has been attributed to the recovery of backscattering that is strongly suppressed in zero magnetic field [2]. In WTe 2 , the large non-saturating MR is believed to arise from perfect electron-hole (e-h) compensation [1], similar to bismuth (Bi) and graphite [4][5][6]. This is supported by angle-resolved photoemission spectroscopy (ARPES) [7] and quantum oscillation [8] experiments, which have found hole and electron pockets with the same size in WTe 2 at low temperatures. Further support for the e-h compensation scenario came from the application of pressure, which increases the difference between the sizes of the hole and electron pockets, dramatically suppressing the MR [9][10][11]. However, a recent high resolution ARPES study revealed a more complicated Fermi surface (FS) with nine pockets [12]. In addition, circular dichroism was observed in the photoemission spectra, signaling strong spin-orbit coupling, which may also play an important role in WTe 2 . Finally, a detailed study of the Shubnikov-de-Haas (SdH) effect, in combination with density functional theory (DFT) calculations, indicated that perfect e-h compensation breaks down under an external magnetic field in WTe 2 [13], challenging the e-h compensation scenario.More insight into the physics of WTe 2 can be obtained using ultrafast optical spectroscopy, which tracks the relaxation of photoexcited carriers in the time domain as they return to equilibrium. Carrier relaxation depends sensitively on the band structure and scattering mechanisms in a solid [14][15][16][17], and therefore an understanding of the ultrafast carrier dynamics in WTe 2 may shed new light on the mechanism of the anomalous MR. This also directly resolves the timescales that ultimately limit potential applications of WTe 2 in electronic devices, e.g., high speed solid-state drives. However, ultrafast optical studies have not yet been performed on this material.Here, we present a detailed ultrafast transient reflectivity (∆R(t)/R) study on WTe 2 while varying the temperatu...

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“…3D and quasi-2D sheets. The latter resemble those in the parent compound USb 2 [26], revealing some nesting features, probably responsible for a spindensity wave formation in this uranium diantimonide [25]. The positions of core-lines of the Sb atoms appear to be quite similar to those reported for the pure element but such lines of the Cu atoms show small chemical shifts.…”

Section: Discussionmentioning

confidence: 60%

“…For this uranium diantimonide, possessing a very complex real structure of the U 5f electrons at the Fermi level, a spin-density wave modulation, driven by such an FS nesting, has been just postulated in Ref. [25]. Moreover, our Fermi surface sheets have more regular shapes and much different topology from those obtained for considered here stoichiometric UCuSb 2 but employing the GGA, GGA + U and GGA + OP functionals, presented in Fig.…”

Section: Fermi Surfacementioning

confidence: 86%

“…The 5f-electron behavior can be as complex as in the case of the parent USb 2 compound [25], for which ultrafast optical spectroscopy (UOS) revealed directly an existence of two subsets of the U 5f electrons that behave in a different manner (as localized and itinerant) at the same time. It is also worth to note that the positions and shapes of experimental peaks of the U 5f and Cu 3d electrons (nos.…”

Section: Densities Of States Overall and Valence Xps Spectra And Magmentioning

confidence: 99%

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X-ray photoemission spectrum, electronic structure, and magnetism of UCuxSb2

Morkowski

Chełkowska

Werwiński

et al. 2015

Journal of Alloys and Compounds

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Measurement of Two Low-Temperature Energy Gaps in the Electronic Structure of AntiferromagneticUSb2Using Ultrafast Optical Spectroscopy

Abstract: Ultrafast optical spectroscopy is used to study the antiferromagnetic f-electron system USb(2). We observe the opening of two charge gaps at low temperatures ( Show more

Cited by 38 publications

References 38 publications

Revealing multiple charge-density-wave orders inTbTe3by optical conductivity and ultrafast pump-probe experiments

Revealing multiple charge-density-wave orders inTbTe3by optical conductivity and ultrafast pump-probe experiments

Ultrafast carrier dynamics in the large magnetoresistance material WTe2

X-ray photoemission spectrum, electronic structure, and magnetism of UCuxSb2

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