Iron-based heavy quasiparticles inSrFe4Sb12: An infrared spectroscopic study

Abstract

Temperature-dependent infrared reflectivity spectra of SrFe4Sb12 has been measured. A renormalized Drude peak with a heavy effective mass and a pronounced pseudogap of 10 meV develops in the optical conductivity spectra at low temperatures. As the temperature decreases below 100 K, the effective mass (m * ) rapidly increases, and the scattering rate (1/τ ) is quenched. The temperature dependence of m * and 1/τ indicates that the hybridization between the Fe 3d spins and the charge carriers plays an important role in determining the physical properties of SrFe4Sb12 at low temperatures. This result is the clear evidence of the iron-based heavy quasiparticles.

Application of spark plasma sintering to the fabrication of binary and ternary skutterudites

“…Alkaline-earth metals and Yb-filled skutterudites are paramagnets but several experimental and theoretical observations demonstrate that they are close to ferromagnetic ordering [4,[5][6][7][8]. In addition, compounds exhibit a pseudogap [9,10] in the infrared optical conductivity which appears at temperatures below 100 K. This phenomenon can be consistently explained by certain sharp peaks in the band structure above E F [9]. All these iron-based compounds are metals albeit with low metallic conductivity [4].…”

Infrared study on the electronic structure of the alkaline-earth-filled skutteruditesAM4Sb12(A=SrKimura1, Im2, Mizuno3 et al. 2007Phys. Rev. BSelf Cite14370View full textAdd to dashboardCite

“…26 The existence of heavy quasiparticles originating from the Fe 3d state has been previously reported. 12 The origin of the heavy quasiparticles is believed to be the Kondo effect resulting from the hybridization between the localized Fe 3d state and conduction band. However, since SrFe 4 Sb 12 is located very near the ferromagnetic ordering state, the spin fluctuation effect must also be considered.…”

“…8,9,10 These skutterudites also produce iron-based heavy quasiparticles as a result. 11,12 The positional parameters u and v of the Sb atoms denoted in Figure 1 on the different A and M atoms. These positional parameters also affect the electronic structure.…”

Anisotropic Electronic Structure of the Kondo Semiconductor CeFe2Al10Studied by Optical Conductivity

“…This result is consistent with our previous optical studies of heavy fermion compounds. [25][26][27] Therefore, the anisotropic T opt implies that T K is also anisotropic. The similar anisotropic T K has been discussed in orthorhombic CeNiSn and CeRhAs, in which no magnetic phase transition takes place.…”

“…The temperature dependence of the residual Drude weight is common to heavyquasiparticles, whose scattering rate declines with decreasing temperature. [25][26][27] Next, the anisotropic formation processes of the c-f hybridization gap and quasiparticle state are discussed. Figure 3(a) indicates the temperature dependence of the low-energy portion of the σ(ω) spectrum along all principal axes.…”