High-pressure synthesis and superconductivity of the novel laves phase BaIr2

Koshinuma, Terunari; Ninomiya, Hiroki; Hase, Izumi; Fujihisa, Hiroshi; Gotoh, Yoshito; Kawashima, Kenji; Ishida, Shigeyuki; Yoshida, Yoshiyuki; Eisaki, H.; Nishio, Toshiyuki; Iyo, A.

doi:10.1016/j.intermet.2022.107643

Cited by 7 publications

(6 citation statements)

References 40 publications

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“…The superconducting penetration depth λ GL (0) can then be obtained from H c1 (0) and ξ GL (0) using the relation: The value is found to be λ GL (0) = 1513 Å for Sc variant, λ GL (0) = 2440 Å for Y variant, and λ GL (0) = 3270 Å for Lu variant. The obtained values are comparable with these reported for the cubic Laves phases e.g., BaIr 2 (1520 Å 45 ), SrIr 2 (2370 Å 36 ) or SrRh 2 (2291 Å 36 ). Furthermore, the GL parameter = λ GL /ξ GL equals 13, 20, and 23 for ScOs 2 , YOs 2 and LuOs 2 , respectively, which are clearly larger than 1/ , implying that all investigated Laves compounds are the type-II superconductors.…”

Section: Resultssupporting

confidence: 88%

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Górnicka,

Winiarski,

Walicka

et al. 2023

Sci Rep

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We have successfully synthesized three osmium-based hexagonal Laves compounds ROs2 (R = Sc, Y, Lu), and discussed their physical properties. LeBail refinement of pXRD data confirms that all compounds crystallize in the hexagonal centrosymmetric MgZn2-type structure (P63/mmc, No. 194). The refined lattice parameters are a = b = 5.1791(1) Å and c = 8.4841(2) Å for ScOs2, a = b = 5.2571(3) Å and c = 8.6613(2) Å for LuOs2 and a = b = 5.3067(6) Å and c = 8.7904(1) Å for YOs2. ROs2 Laves phases can be viewed as a stacking of kagome nets interleaved with triangular layers. Temperature-dependent magnetic susceptibility, resistivity and heat capacity measurements confirm bulk superconductivity at critical temperatures, Tc, of 5.36, 4.55, and 3.47 K for ScOs2, YOs2, and LuOs2, respectively. We have shown that all investigated Laves compounds are weakly-coupled type-II superconductors. DFT calculations revealed that the band structure of ROs2 is intricate due to multiple interacting d orbitals of Os and R. Nonetheless, the kagome-derived bands maintain their overall shape, and the Fermi level crosses a number of bands that originate from the kagome flat bands, broadened by interlayer interaction. As a result, ROs2 can be classified as (breathing) kagome metal superconductors.

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Section: Resultssupporting

confidence: 88%

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Górnicka,

Winiarski,

Walicka

et al. 2023

Sci Rep

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“…Consequently, the coherence length, ξGL, can be estimated using the Ginzburg-Landau formula 𝐻 *7 = Ф G /2𝜋𝜉 ij 7 , where Ф0 = hc/2e is the quantum flux. Having µ0Hc2(0) values, the GL coherence length ξGL The obtained values are comparable with these reported for the cubic Laves phases e.g., BaIr2 (1520 Å [45]), SrIr2 (2370 Å [36]) or SrRh2 (2291 Å [36]). Furthermore, the GL parameter κ ij = λGL/ξGL equals 13, 20, and 23 for ScOs2, YOs2 and LuOs2, respectively, which are clearly larger than 1/√2, implying that all investigated Laves compounds are the type-II superconductors.…”

Section: Resultssupporting

confidence: 82%

Superconductivity in a breathing kagomé metals ROs2 (R = Sc, Y, Lu)

Górnicka,

Winiarski,

Walicka

et al. 2023

Preprint

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We have successfully synthesized three osmium-based hexagonal Laves compounds ROs2 (R = Sc, Y, Lu), and discussed their physical properties. LeBail refinement of pXRD data confirms that all compounds crystallize in the hexagonal centrosymmetric MgZn2 – type structure (P63/mmc, No. 194). The refined lattice parameters are a = b = 5.1791(1) Å and c = 8.4841(2) Å for ScOs2, a = b = 5.2571(3) Å and c = 8.6613(2) Å for LuOs2 and a = b = 5.3067(6) Å and c = 8.7904(1) Å for YOs2. ROs2 Laves phases can be viewed as a stacking of kagomé nets interleaved wih triangular layers. Temperature-dependent magnetic susceptibility, resistivity and heat capacity measurements confirm bulk superconductivity with Tc = 5.36, 4.55, and 3.47 K for ScOs2, YOs2, and LuOs2, respectively. We have shown that all investigated Laves compounds are weakly-coupled type-II superconductors. DFT calculations revealed that the band structure of ROs2 is intricate due to multiple interacting d orbitals of Os and R. Nonetheless, the kagomé-derived bands maintain their overall shape, and the Fermi level is found originates from the kagomé flat bands that are broadened by interlayer interaction. As a result, ROs2 can be classified as (breathing) kagomé metal superconductors.

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“…Given that the Fermi surfaces of ZrIr 2 are quite different (and much simpler) compared with AIr 2 (A = Sr or Th), [23,24] it will possibly provide new thoughts for understanding the superconductivity in Irbased C15-type superconductors. SrIr 2 [22] SrIr 2 [23] BaIr 2 [25] ThIr 2 [24] T c (K) 4.0 5.8 5.9…”

Section: Discussionmentioning

confidence: 99%

“…Recently, Ir-based C15-type Laves phases AIr 2 (A = Ca, Sr, Ba, Th) have attracted much interest for the coexistence of superconductivity and strong spin-orbit coupling (SOC) effects. [20][21][22][23][24][25][26] Although superconductivity in AIr 2 (A = Ca, Sr, Th) had been discovered before the 1960s, [27] the normal-state and superconducting properties of AIr 2 were not systematically studied until these recent reports. Electronic band structure calculations further revealed that the presence of SOC would strongly affect not only the topology of Fermi surfaces but also the lattice stability.…”

Section: Introductionmentioning

confidence: 99%

Superconducting properties of the C15-type Laves phase ZrIr₂ with an Ir-based kagome lattice

et al. 2023

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We report systematic studies on superconducting properties of the Laves phase superconductor ZrIr$_2$. It crystallizes in a C15-type (cubic MgCu$_2$-type, space group $Fd\overline{3}m$) structure in which the Ir atoms form a kagome lattice, with cell parameters $a=b=c=7.3596(1)$ Å. Resistivity and magnetic susceptibility measurements indicate that ZrIr$_2$ is a type-II superconductor with a transition temperature of 4.0 K. The estimated lower and upper critical fields are 12.8 mT and 4.78 T, respectively. Heat capacity measurements confirm the bulk superconductivity in ZrIr$_2$. ZrIr$_2$ is found to possibly host strong-coupled $s$-wave superconductivity with the normalized specific heat change $\Delta C_e/\gamma T_c$ $\sim$ 1.86 and the coupling strength $\Delta_0/k_BT_c$ $\sim$ 1.92. First-principles calculations suggest that ZrIr$_2$ has three-dimensional Fermi surfaces with simple topologies, and the states at Fermi level mainly originate from the Ir-5$d$ and Zr-4$d$ orbitals. Similar to SrIr$_2$ and ThIr$_2$, spin-orbit coupling has dramatic influences on the band structure in ZrIr$_2$.

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High-pressure synthesis and superconductivity of the novel laves phase BaIr2

Cited by 7 publications

References 40 publications

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Superconductivity in a breathing kagomé metals ROs2 (R = Sc, Y, Lu)

Superconducting properties of the C15-type Laves phase ZrIr₂ with an Ir-based kagome lattice

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High-pressure synthesis and superconductivity of the novel laves phase BaIr2

Cited by 7 publications

References 40 publications

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Superconductivity in a breathing kagome metals ROs2 (R = Sc, Y, Lu)

Superconductivity in a breathing kagomé metals ROs2 (R = Sc, Y, Lu)

Superconducting properties of the C15-type Laves phase ZrIr2 with an Ir-based kagome lattice

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Superconducting properties of the C15-type Laves phase ZrIr₂ with an Ir-based kagome lattice