Hypervalent Bismuthides La₃MBi₅ (M = Ti, Zr, Hf) and Related Antimonides: Absence of Superconductivity

Abstract

We successfully synthesized the ternary bismuthides LaMBi (M = Ti, Zr, Hf). These compounds crystallize in the hexagonal HfSnCu-anti type structure (space group: P6/mcm) consisting of face-sharing MBi octahedral chains and hypervalent Bi linear chains, both separated by La atoms. Magnetic susceptibility and electrical resistivity measurements revealed that all of the compounds, including the solid solution LaTi(BiSb), exhibit a Pauli paramagnetic behavior without any trace of superconductivity down to 1.85 K, as opposed to a recently reported 4 K superconductivity in LaTiSb. The absence of superconductivity is supported by first-principles band calculations of LaTiBi and LaTiSb that demonstrate similar electronic structures with three-dimensional Fermi surfaces.

Undistorted linear Bi chains with hypervalent bonding in La3TiBi5 from single-crystal X-ray diffraction

“…A powder X-ray diffraction (PXRD) study of the ground crystals was performed on a Rigaku Miniflex diffractometer (Cu K radiation, = 1.5418 Å ) operating inside a nitrogenfilled glove-box in a Â-Â scan mode with a step size of 0.05 and a 2 s per step acquisition time. According to the PXRD analysis, the crystals were revealed to be the recently reported La 3 TiBi 5 phase (Murakami et al, 2017). Since its crystal structure was originally refined from PXRD data and showed an anomaly of the Ti displacement parameter, we conducted a more accurate single-crystal X-ray diffraction investigation.…”

“…Of particular relevance to this paper are the bismuthides La 3 MBi 5 (M = Ti, Zr, and Hf), which show metallic behavior with no phase transitions down to 1.85 K (Murakami et al, 2017). The structural work has been carried out on polycrystalline samples, and one can notice that the Reitveld refinement for La 3 TiBi 5 , although of very high quality and converging to low residual factors (Murakami et al, 2017), leads to a small ambiguity. Namely, an unusually large isotropic displacement parameter of the Ti atom is reported, while the other refined structures, those of La 3 ZrBi 5 and La 3 HfBi 5 show no such anomalies at the transition metal site.…”

“…Recently, new rare-earth bismuthides with the composition La 3 MBi 5 (M = Ti, Zr, and Hf) have been reported (Murakami et al, 2017). The series RE 3 MnBi 5 (RE = La-Nd) has also been structurally characterized (Zelinska & Mar, 2008).…”

Synthesis, Crystal and Electronic Structure of the Titanium Bismuthides Sr5Ti12Bi19+x, Ba5Ti12Bi19+x, and Sr5–δEuδTi12Bi19+x (x ≈ 0.5–1.0; δ ≈ 2.4, 4.0)

“…These compounds are metals, though their magnetic properties arising from the rare‐earth metal f ‐electrons have been studied only for a few of them . Much less is known about the ternary phases existing in the RE –Ti–Bi systems, where only La 3 TiBi 5 has been described . The only ternary compounds reported in the AE –Ti– Pn systems ( Pn = P, As, Sb), where AE is an alkaline‐earth metal, are the Zintl phases AE 4 Ti Pn 4 ( AE = Sr, Ba; Pn = P, As) and the metallic compound Ba 5 Ti 12 Sb 19+ x .…”

A new quasi-one-dimensional compound Ba3TiTe5 and superconductivity induced by pressure

“…However, the complementary calculation proves that there are non-negligible contributions of La to the density of state (DOS) at the Fermi level. The La 3+ ions in La 3 TiSb 5 are not perfectly ionic, which leads to a 3D band structure 32 . It is strongly indicated that La atoms do not play the role of interchain separation but serve as a bridge for electrons hopping among the chains.…”