π-Donor BETS Based Bifunctional Superconductor with Polymeric Dicyanamidomanganate(II) Anion Layer: κ-(BETS)₂Mn[N(CN)₂]₃

Abstract

Crystals of the bis(ethylenedithio)tetraselenafulvalene (BETS) radical cation salt with dicyanamidomanganate(II) anion, kappa-(BETS)2Mn[N(CN)2]3, were synthesized, which combine conducting and magnetic properties at ambient pressure and are superconducting (Tc approximately/= 5 K) at a moderate pressure of 0.3 kbar.

Properties of Mn2+ and Π-Electron Spin Systems Probed by 1H and 13C NMR in the Organic Conductor κ-(BETS)2Mn[N(CN)2]3

“…In complex compounds incorporating more than one electron spin system (e.g., itinerant and localized electrons) such information helps to discriminate between the events developing within the electron subsystems and determine the interrelation between them. The quasi-two-dimensional organic conductor κ-(BETS) 2 Mn[N(CN) 2 ] 3 (BETS = C 10 S 4 Se 4 H 8 , bis-(ethylenedithio)tetraselenafulvalene) is an example of such compound ( Figure 1). The system is metallic down to T MI ∼ 23 K where it undergoes the metal-insulator (MI) transition [1,2].…”

“…The quasi-two-dimensional organic conductor κ-(BETS) 2 Mn[N(CN) 2 ] 3 (BETS = C 10 S 4 Se 4 H 8 , bis-(ethylenedithio)tetraselenafulvalene) is an example of such compound ( Figure 1). The system is metallic down to T MI ∼ 23 K where it undergoes the metal-insulator (MI) transition [1,2]. Its conductivity is associated with π-electrons confined within the layers of dimerised organic BETS molecules, sandwiched between the insulating polymeric Mn[N(CN) 2 ] 3 anion layers, while the bulk magnetization is determined by Mn 2+ (J = S = 5/2, L = 0) ions of the anion layers [3].…”

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

“…Single crystals of κ-(BETS) 2 Mn[N(CN) 2 ] 3 were grown electrochemically, as described elsewhere [18] and had a shape of small plates with characteristic dimensions of ≃ 0.5 × 0.3 × 0.02 mm 3 . The largest surface of the plate was parallel to the highly conducting BETS molecular layers, which is defined as the crystallographic bc-plane.…”

“…The electrical conductivity is provided by delocalized π electrons of fractionally charged BETS donors arranged in two-dimensional (2D) sheets, whereas magnetic * mark.kartsovnik@wmi.badw.de properties are dominated by localized d-electron spins of Mn 2+ in the insulating anionic layers [18]. In addition to the interesting, still not understood crosstalk between the two subsystems [19][20][21], the narrow, half-filled conduction band is a likely candidate for a Mott instability [22].…”

“…In addition to the interesting, still not understood crosstalk between the two subsystems [19][20][21], the narrow, half-filled conduction band is a likely candidate for a Mott instability [22]. The material undergoes a metal-insulator transition at ≈ 21 K [18,22]. The insulating ground state is very sensitive to pressure: under a quasi-hydrostatic pressure of about 1 kbar it is completely suppresses, giving way to a metallic and even a superconducting state with T c ≈ 5 K [22].…”