Single-crystal growth and physical properties of the layered arsenideBaRh2As2

Abstract

Single crystals of BaRh2As2 have been synthesized from a Pb flux. We present the room temperature crystal structure, single crystal x-ray diffraction measurements as a function of temperature T , anisotropic magnetic susceptibility χ versus T , electrical resistivity in the ab-plane ρ versus T , Hall coefficient versus T and magnetic field H, and heat capacity C versus T measurements on the crystals. The single crystal structure determination confirms that BaRh2As2 forms in the tetragonal ThCr2Si2 type structure (space group I4/mmm) with lattice parameters a = b = 4.0564(6)Å and c = 12.797(4)Å. Band structure calculations show that BaRh2As2 should be metallic with a small density of states at the Fermi energy N (EF) = 3.49 states/eV f.u. (where f.u.≡ formula unit) for both spin directions. ρ(T ) data in the ab-plane confirm that the material is indeed metallic with a residual resistivity ρ(2 K) = 29 µΩ cm, and with a residual resistivity ratio ρ(310 K)/ρ(2 K) = 5.3. The observed χ(T ) is small (∼ 10 −5 cm 3 /mol) and weakly anisotropic with χ ab /χc ≈ 2. The C(T ) data indicate a small density of states at the Fermi energy with the low temperature Sommerfeld coefficient γ = 4.7(9) mJ/mol K 2 . There are no indications of superconductivity, spin density wave, or structural transitions between 2 K and 300 K. We compare the calculated density of states versus energy of BaRh2As2 with that of BaFe2As2.

Superconductivity without Fe or Ni in the phosphidesBaIr2P2andBaRh2PBerry1, Capan2, Seyfarth3 et al. 2009Phys. Rev. B4210450View full textAdd to dashboardCite

“…30 Future studies should clarify the effect of the Fe moments on T c . In addition, BaRh 2 As 2 exhibits no superconductivity down to 1.8 K. 31 Thus, the relationship between the tetragonal structure and SC is not clear at present in the 122 arsenides. The present phosphides allow the investigation of the relationship between SC and structure without the interference of magnetism since neither Rh nor Ir is intrinsically magnetic.…”

Type II superconductivity in SrPd2Ge2

“…Still, the mechanism responsible for superconductivity in iron pnictides is unclear to date and the roles of magnetic, chemical and structural properties of the compounds remain an issue. To unravel it, already several pnictide superconductors without magnetic elements were studied [14][15][16][17][18][19]. These isostructural materials serve as a playground for investigating the role of the structure in the mechanism of superconductivity in the absence of a magnetic element.…”

Electronic properties of novel 6 K superconductor LiFeP in comparison with LiFeAs from first principles calculations

“…These materials, where magnetic metal (Fe) is completely replaced by the other 3d magnetic metal (Ni) or non-magnetic metals (Ru, Rh) arsenic is completely replaced by other pnictogen -phosphorus, belong to the above mentioned "122" family and are low-temperature SC's (T C ~ 0.3-3.0K), see [21][22][23][24].…”