Quantum oscillation studies of the Fermi surface of iron-pnictide superconductors

Abstract

Abstract. This paper reviews quantum oscillation studies of iron-pnictide superconductors and related materials. These measurements give unique information regarding the full three dimensional topology of the Fermi surfaces and the renormalisation of the quasi-particle masses. The review will cover measurements of the 122 arsenide end members, XFe 2 As 2 (X = Ba, Sr, Ca) which have a spin density wave ground state, but will concentrate on the phosphide end members (LaFePO and XFe 2 P 2 ) which have a paramagnetic ground state and a Fermi surface topology which is similar to the higher T c superconducting iron-pnictides. All three of the 122 phosphides become superconducting when P is partially substituted by As, and for the BaFe 2 (As 1−x P x ) 2 series de Haas-van Alphen oscillations are observable for 0.42 ≤ x ≤ 1 with T c up to 25 K. The results show the changes in the Fermi surface topology and the increase in the mass renormalisation as the correlations which induce superconductivity develop.

Nodal superconductivity in isovalently substituted SrFe2(As1−xPxMurphy1, Strehlow2, Cho3 et al. 2013Phys. Rev. B229160View full textAdd to dashboardCite

“…inset shows the data zoomed in the vicinity of T c . Overall, the resistivity curves for SrP122 and BaP122 are virtually the same showing clear deviation from the Fermi liquid T 2 dependence at all temperatures, indicating proximity to the quantum critical point at the optimal doping [18,31,33,[40][41][42]. Figure 2 shows the low temperature behavior of the penetration depth for three samples of SrFe 2 (As 1−x P x ) 2 .…”

“…This difference must be due to the difference in the gap magnitudes and anisotropies in these multi-gap systems, but the low -temperature behavior is determined by the nodal quasiparticles and the similarity of the data implies that the nodal structure of SrP122 and BaP122 is similar. The deviation from the 2D d−wave could be due to geometry of the nodal lines, -perhaps forming the loops in the electron bands [17,20,31,[49][50][51].…”

Nearly massless Dirac fermions and strong Zeeman splitting in the nodal-line semimetal ZrSiS probed by de Haas–van Alphen quantum oscillations

“…In general, for a system showing Landau level quantization, the increased degeneracy of Landau levels leads to enhanced density of state near the Fermi level under high magnetic fields, which effectively amplifies the electron correlation effect [90][91][92]. This effect is expected to be particularly strong for the α-Dirac band of ZrSiS since the quantum limit of this band can be easily reached due to its low oscillation frequency (F α ~8.4T).…”

Shubnikov–de Haas oscillations and electronic correlations in the layered organic metal κ-(BETS)2 Mn[N(CN)2]3

“…Besides traditional metals, quantum oscillations of magnetoresitance (Shubnikov -de Haas, SdH effect) and magnetization (de Haasvan Alphen effect) have recently proved extremely useful in exploring more complex topical materials such as cuprate [4,5] and iron-based superconductors [6][7][8], topological insulators [9][10][11], heavy fermion compounds [12][13][14], and organic charge-transfer salts [15][16][17]. Here we report on an experimental study of the high-field interlayer magnetoresistance of the layered conductor κ-(BETS) 2 Mn[N(CN) 2 ] 3 , demonstrating the power of the SdH effect in exploring Fermi surface properties of a quasi-two-dimensional correlated electronic system.…”