Repozytorium publikacji - Politechnika Gdańska

CuTeO4 has been proposed as a crystallographically distinct, yet electronic structure analog, of the superconducting cuprates. Here, we present a detailed characterization of the physical properties of CuTeO4 to address this proposal. Fitting of magnetic susceptibility data indicates unexpected quasi-one-dimensional, antiferromagnetic correlations at high temperature, with a nearest-neighbor Heisenberg exchange of 1=164⁢(5) K. Low-temperature heat capacity measurements reveal a sizable -linear contribution of =9.58⁢(8) mJ mol−1K−2, qualitatively consistent with expectations for a =1/2, uniform, Heisenberg spin chain. Below ≈40 K, the susceptibility shows an upturn inconsistent with quasi-one-dimensional behavior. While heat capacity measurements show no signs of magnetic order down to low-temperature, the upturn in the magnetic susceptibility coincides with the emergence of a diffuse peak (centered at | ⃗ ⁢|≈0.7 Å) in the neutron diffraction data, indicative of persistent, short-range, antiferromagnetic order with a correlation length of =10.1⁢(9) Å at =10 K. The onset of nonlinearity and hysteresis in the isothermal magnetization curves suggests the presence of a small ferromagnetic component. This persistent, short-range order is understood in the context of structural modeling of the x-ray and neutron diffraction data that show the presence of a significant density of stacking faults. No evidence for substantive dopability is observed and CuTeO4 appears, qualitatively, to have a larger band gap than predicted by density functional theory. We ascribe this finding to the inductive withdrawal effect from high-valence Te and suggest that superconductivity in copper tellurates is more likely to be found in compounds with a decreased reductive withdrawal effect from Te.

Autorzy

• Zubia Hasan,
• Eli Zoghlin,
• dr inż. Michał Winiarski link otwiera się w nowej karcie ,
• Kathryn E. Arpino,
• Thomas Halloran,
• Thao Tran,
• Tyrel McQueen