Pair-breaking effects and coherence peak in the terahertz conductivity of superconductingBaFe2−2xCo2xAs

Millimeter-wave surface impedance of optimally-doped Ba(Fe1−xCox)2Barannik1, Cherpak2, Tanatar3 et al. 2013Phys. Rev. B284320View full textAdd to dashboardCite

“…The temperature-dependent quasiparticle conductivity, σ 1 (T ) does not show a peak below or at T c , consistent with another microwave study at the lower frequency of 13 GHz [17], but in a stark disagreement with optical and THz measurements on thin films [18,19] and with rather low frequency measurements at 50 kHz [43]. The quasiparticle conductivity increases monotonically on cooling below T c suggesting strong inelastic scattering even at low temperatures.…”

“…Single crystals were measured using essentially DC measurements by magnetic -force microscopy and scanning SQUID [9,10], radio -frequency tunnel -diode resonator [11][12][13] and muon spin rotation (µSR) in vortex state [14,15] and in Meissner state [16], as well as microwave -range measurements [14][15][16][17]. THz and optical refelectivity measurements were performed on thin films [18,19].…”

London penetration depth in iron base superconductors*

“…These include muon-spin rotation (μSR) (Luetkens et al, 2008;Williams et al, 2010;Sonier et al, 2011), frequency-dependent conductivity (Valdés Aguilar et al, 2010;Wu et al, 2010), magnetic force and superconducting quantum interference device (SQUID) microscopy (Luan et al, 2010(Luan et al, , 2011, determinations of the first critical field using either global Song et al, 2011) or local probes Klein et al, 2010), microwave cavity perturbation (Hashimoto et al, 2009a, b;Shibauchi et al, 2009;Bobowski et al, 2010;Takahash et al, 2011), mutual inductance (particularly suitable for thin films; Yong et al, 2011), and self-oscillating tunnel-diode resonator (TDR; Prozorov et al, 2009a;Shibauchi et al, 2009;Malone et al, 2009;Gordon et al, 2010;Kim et al, 2011a,b;Martin et al, 2009aMartin et al, , b, 2010a.…”

On the determination of the quasiparticle scattering rate in unconventional superconductors by microwave surface impedance

“…Superconducting single crystals and films were measured using dc signal by, e.g., magnetic-force microscopy and scanning SQUID. 6,7 Measurements by means of radiofrequency tunnel-diode resonators, 8-10 microwave-range resonance cavities [11][12][13][14][15] as well as THz and optical reflectivity 16,17 techniques have also been reported.…”