Interplay between superconductivity and magnetism in Fe_1−xPd_xTe

Abstract

The attractive/repulsive relationship between superconductivity and magnetic ordering has fascinated the condensed matter physics community for a century. In the early days, magnetic impurities doped into a superconductor were found to quickly suppress superconductivity. Later, a variety of systems, such as cuprates, heavy fermions, and Fe pnictides, showed superconductivity in a narrow region near the border to antiferromagnetism (AFM) as a function of pressure or doping. However, the coexistence of superconductivity and ferromagnetic (FM) or AFM ordering is found in a few compounds [RRh 4 B 4 (R = Nd, Sm, Tm, Er), R′Mo 6 X 8 (R′ = Tb, Dy, Er, Ho, and X = S, Se), UMGe (M = Ge, Rh, Co), CeCoIn 5 , EuFe 2 (As 1−x P x ) 2 , etc.], providing evidence for their compatibility. Here, we present a third situation, where superconductivity coexists with FM and near the border of AFM in Fe 1−x Pd x Te. The doping of Pd for Fe gradually suppresses the first-order AFM ordering at temperature T N/S , and turns into short-range AFM correlation with a characteristic peak in magnetic susceptibility at T ′ N . Superconductivity sets in when T ′ N reaches zero. However, there is a gigantic ferromagnetic dome imposed in the superconducting-AFM (short-range) cross-over regime. Such a system is ideal for studying the interplay between superconductivity and two types of magnetic (FM and AFM) interactions. Since the first discovery of superconductivity (SC) a century ago, the effects of magnetic impurities and the possibility of magnetic ordering in superconductors has been a central topic of condensed matter physics. Due to strong spin scattering (1, 2), it has generally been believed that the conduction electrons cannot be both magnetically ordered and superconducting. Even though it is thought that Cooper pairs in cuprates, heavy fermions, and Fe-based compounds are mediated by spin fluctuations (3-5), SC generally occurs after suppressing the magnetic ordering either through chemical doping or the application of hydrostatic pressure (6-10). However, there is growing evidence for the coexistence of superconductivity with either ferromagnetic (FM) (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) or antiferromagnetic (AFM) ordering (21-24). With the decrease of temperature (T), some of these systems show magnetic ordering before the superconducting transition (T c ) (14-17, 20), some are ordered in a reversed sequence (11-13, 18, 19, 22), some have the two orderings occur concomitantly (22,25), and some show reentrant superconductivity (partially) overlapping with a magnetically ordered phase (11)(12)(13)26). Despite extensive investigations of interaction between SC and magnetic moments, there is so far no unified theory for the coexistence of SC and magnetism. With the lack of theoretic guidance, the existing experimental findings lead to two schools of thought: one is that both orders result from the same conduction electrons as evidenced by their synchronized magnetic and superconducting orders (22), and the other is that there are two s...

First-principles study of the electronic properties of Pd1−xNixTe alloys

“…This is consistent with the experimental results [9]. It is worth mentioning that the Fe doping in PdTe leads to a very rich phase diagram where ferromagnetism coexists with short-range antiferromagnetism and superconductivity [41]. We will discuss the results of spin-unpolarized calculations only.…”

“…In an attempt to explain the phase diagram of Fe 1−x Pd x Te, Jin-Jin et al [7] have studied the effects of Fe doping in PdTe using a supercell method. The density of states at the Fermi energy increases monotonically from 2.50 to 3.07 stateseV −1 per unit cell with increasing Fe concentration, but the superconducting transition temperature T c decreases monotonically with Fe concentration [41]. This is generally attributed to the magnetic nature of iron, but it is also possible that the superconductivity in PdTe is not purely s-wave, as speculated in [4].…”

“…Recently, Karki et al [41] have mapped out the complete phase diagram of Fe 1−x Pd x Te from FeTe (for x = 0) to PdTe (for x = 1). Indeed, Fe 1−x Pd x Te has a very rich phase diagram.…”

Pseudogap and proximity effect in the Bi2Te3/Fe1+yTe interfacial superconductor

“…1)34 and thus does not appear to be related to its magnetic ordering. Similar to Se-doped FeTe, it is likely that the magnetic order in the interface region is weakened by charge transfer across the interface from the n -doped Bi 2 Te 3 layer.…”

Role of chalcogen vapor annealing in inducing bulk superconductivity inFe1+yTe1−xSex

“…We show that the remaining FeTem complexes are still damaging to the superconductivity and therefore that their removal potentially could further improve superconductive properties in these compounds. The interplay between magnetism and superconductivity in cuprate, heavy-fermion and iron-based superconductors has attracted intensive interest of the research community [1][2][3]. Superconductivity and magnetic ordering are usually considered to be incompatible.…”