Effect of annealing on the specific heat of Ba(Fe1−xCox)

K. Gofryk

¹

,

A. B. Vorontsov

²

,

Ilya Vekhter

³

et al.

Robust accidental nodes and zeros and critical quasiparticle scaling in iron-based multiband superconductors

“…In 122s -the best studied compounds of this family -the angle resolved photoemission spectroscopy (ARPES) [8][9][10] detects up to four relatively isotropic gaps, one for each of the two hole and two electron bands of the FS. This is in an apparent contradiction to the penetration depth 11,12 , thermal conductivity 13 and specific heat data 14,15 , which indicate gapless quasiparticle excitations -a natural interpretation is that these are associated with nodes in the gap somewhere along the (multiply-connected) FS. Moreover, Refs.…”

Calorimetric evidence of strong-coupling multiband superconductivity in Fe(Te0.57Se0.43)

“…A variety of intriguing properties of iron pnictide superconductors have been revealed from specific heat measurements. For instance, the electronic specific heat C e is found to not vanish in zero-temperature limit even for optimally-doped samples [25][26][27][28][29][30][31][32][33][34] 35 . This scaling law cannot be understood in term of BCS-theory, but implies that quantum criticality may play an important role in mediating superconductivity 36 .…”

“…Critical information on superconducting pairing symmetry is also revealed from specific heat measurements. The electronic specific heat at SC state can be described well using a two-band model with isotropic s-wave gaps [28][29][30][31] or anisotropic s-wave gaps 34,37 .…”

Polarized neutron diffraction study of the field-induced magnetization in the normal and superconducting states of Ba(Fe1−xCox)Lester1, Chu2, Analytis3 et al. 2011Phys. Rev. B

“…It has been studied widely by various probes including angle-resolved photoemission spectroscopy (ARPES) 5 , scanning tunnel microscopy (STM) 6 , penetration depth 7,8 , µSR 9 , heat capacity 10,11 and thermal conductivity 4 . Even in this single system, different gap characters have been proposed as a function of doping, including fully and nodally gapped structures [4][5][6][7][9][10][11] . Here we use half-polarized neutron diffraction to measure the susceptibility and induced magnetization in the normal and superconducting states of near optically doped Ba(Fe 1−x Co x ) 2 As 2 (x = 0.065).…”