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

Abstract

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).

Terahertz Spectra Revealing the Collective Excitation Mode in Charge‐Density‐Wave Single Crystal LuFe 2 O 4

“…On the other hand, herein, the value of Γ is on the same order of that observed in Pr 0.7 Ca 0.3 MnO 3 . Therefore, qualitatively and quantitatively, our observation of low‐frequency collective excitation is in fair agreement with previous experiments reporting the CDW in several manganite systems and layered system …”

Anisotropy of conductivity in rare-earth tritellurides in the static and sliding states of the CDW

“…1 a). This maximum may be explained by the opening of new energy gap at around 165 K, revealed by both infrared reflectivity spectroscopy and ultrafast pump-probe spectroscopy [15]. Below this temperature anisotropy decreases monotonically up to T ¼41 K where a sharp increase of anisotropy has been observed.…”

Coexistence and competition of multiple charge-density-wave orders in rare-earth tritellurides

“…The formation of the peak or maximum in σ 1 (ω) is caused by both the density of state and the type I coherence factor effect. 1,2 To quantify the discussions, a Drude-Lorentz model was employed to extract the CDW gap sizes and the relevant spectral weight, [12][13][14] as will be presented below in detail. Figure 2 shows the optical spectra of the whole RTe 3 series at two representative temperatures 10 K and 300 K. For each compound multiple suppressions in R(ω) arise at 10 K and simultaneously multiple peaks appear in σ 1 (ω).…”