Electronic nematicity revealed by torque magnetometry inEuFe2(As1−xPx)2

Abstract

Electronic nematics, an electron orientational order which breaks the underlying rotational symmetry, have been observed in iron pnictide superconductors several years after their discovery. However, the universality of the doping dependence of this phase and its relation to other symmetrybreaking orders (such as superconductivity) in distinct families of iron pnictides, remain outstanding questions. Here we use torque magnetometry as a probe to study the rotational symmetry breaking in EuFe2(As1−xPx)2 without introducing external pressure. The nematic phase is found to proliferate well above the structural transition and to persist into the superconducting regime at optimal doping, after which it becomes absent or very weak, in sharp contrast to the behaviour observed in BaFe2(As1−xPx)2. These measurements suggest a putative quantum nematic transition near optimal doping under the superconducting dome.

Domain Meissner state and spontaneous vortex-antivortex generation in the ferromagnetic superconductor EuFe 2 (As 0.79 P 0.21 ) 2

“…Single crystals of EuFe 2 (As 0.79 P 0.21 ) 2 were grown using a self-flux method ( 8 ). The actual chemical composition of the studied samples was determined using energy-dispersive x-ray analysis on Carl Zeiss Supra 50VP scanning electron microscope.…”

“…1, A to C). Below T FM , the two orders coexist ( 4 – 8 ). It is precisely the competition between them that results in unprecedented SC phases with internal spatial structure at nanoscale, as we show below.…”

Phase diagram of Eu magnetic ordering in Sn-flux-grown Eu(Fe1−xCox)2AsJin1, Xiao2, Bukowski3 et al. 2016Phys. Rev. B302460View full textAdd to dashboardCite

“…17,20 It is quite clear that the physical properties of the Eu(Fe 1−x Co x ) 2 As 2 single crystals strongly depend on the growth techniques. Furthermore, in contrast to EuFe 2 (As 1−x P x ) 2 system whose phase diagram was already thoroughly investigated, 16,[23][24][25][26] a specific phase diagram of Eu(Fe 1−x Co x ) 2 As 2 describing how the magnetic order of the Eu 2+ moments develops with Co doping and how it is linked with the occurrence of SC has not been established yet.…”

Combined resistivity and Hall effect study on NaFe1−xRhxAs single crystals

“…Thus, in order to study the zero-strain fluctuations other methods were applied. Nuclear magnetic resonance (NMR), 15,17,18 magnetic torque measurements, 19,20 X-ray absorption spectroscopy, 21 point contact spectroscopy 22 as well as angle resolved photoemission spectroscopy (ARPES) 23 were able to detect a fluctuation regime in doped 111 and 122 compounds. However, the question about the temperature and doping evolution of the fluctuation regime in the phase diagram of the Fe-based superconductors remains open.…”