Spin-crossover and high magnetic anisotropy in organometallic structures: W3C6O6 and Re3C6O6

Organometallic monolayers of the form TM 3 C 6 O 6 where TM is any possible transition metal are a very promising material class. Some members of this family with 3 d transition metals had been synthesized on noble metal surfaces and we extend here the study to two metals, Tungsten (W) and Rhenium (Re), of the 5 d series by the use of ab-initio calculations. One of the key findings is the discovery of spin-crossover behavior in both monolayers. Especially interesting is the spin-crossover behavior of Re 3 C 6 O 6 which exhibits a transition from intermediate-spin (semiconducting) to high-spin (metallic) states, leading to a significant change in the bandgap, affecting its electrical behavior. In W 3 C 6 O 6 , a small gap in the electronic band structure has been observed. Furthermore, a remarkable high magnetic anisotropy energy has been found in these organometallics with 5 d transition metals. Besides the ab-initio energy differences, also the parameters of a Heisenberg model with local anisotropy energies have been determined. The presence of high magnetic anisotropy energies in these organometallics makes them beneficial for potential technological applications, particularly in magnetic storage, spintronics, and other magnetic-based technologies. The high magnetic anisotropy also holds promise for quantum computing, where stable and robust magnetic qubits are essential for information storage and manipulation. Additionally, these materials with high magnetic anisotropy energies are of great interest in fundamental research as they can provide valuable insights into the underlying magnetic interactions and electronic structure of the compounds. In summary, our study highlights the fascinating properties of TM 3 C 6 O 6 organometallics, with implications for future technologies, quantum computing, and fundamental research in the field of magnetic materials. Furthermore, the discovery of spin-crossover behavior of these materials opens up exciting possibilities for their use in future technologies and epitaxy on different substrates.