Structural and magnetic properties of TlTF3 (T=Fe, Co and Ni) by hybrid functional theory

• TlTF3 (T=Fe, Co and Ni) perovskites are investigated theoretically by hybrid density functional theory.
• Mechanical properties explain the hardness of these compounds and show that TlFeF3 is more ductile.
• The bandgap calculations show that TlFeF3 and TlCoF3 are metallic, whereas TlNiF3 is a wide bandgap semiconductor.
• Magnetic optimizations and magnetic susceptibility confirm that TlFeF3 and TlNiF3 are ferromagnetic whereas TlCoF3 is anti-ferromagnetic material.

DFT studies are performed to investigate the structural, mechanical and magneto-electronic properties of the TlTF3 (T=Fe, Co and Ni) perovskites for the first time using GGA, GGA+U and hybrid density functional theory (HF). Our calculations show that HF give better results than GGA and GGA+U and more consistent with the experiments. The comparison of the lattice constants calculated by HF with experiments shows a maximum underestimation less than 0.2%. The chemical bonding between different ions in these compounds is explained on the bases of electronic clouds, which reveals that in TlFeF3, Fe has more ionic character with F than the rest. The mechanical properties explain the hardness of these compounds and show that TlFeF3 is more ductile. Spin-dependent electronic band profiles show that TlFeF3 and TlCoF3 are metallic, whereas TlNiF3 is pseudo direct wide bandgap semiconductor. The stable magnetic phase optimizations and the calculated magnetic susceptibility confirm that TlFeF3 and TlNiF3 are ferromagnetic whereas TlCoF3 is anti-ferromagnetic material.