Researchers Trishu Verma, Shivani Bhardwaj, and Sudhir K Pandey from the Indian Institute of Technology Roorkee have recently published a study in the journal Physical Review B, exploring the magnetic and spectral properties of alpha iron (α-Fe) as a function of temperature. Their work delves into the influence of electronic correlations and plasmonic excitations on the valence band satellite of α-Fe, providing insights that could have practical implications for the energy industry.
The researchers employed advanced computational methods, including constrained random phase approximation (cRPA) and Density Functional Theory plus Dynamical Mean Field Theory (DFT+DMFT), to investigate the electronic structure of α-Fe. They identified a valence band satellite at approximately 6 eV binding energy, supported by significant incoherent spectral weight in the valence band spectra and plasmonic excitations in the frequency range of 6-8 eV.
One of the key findings of the study is the significant contribution of temperature-dependent Pauli-spin susceptibility, indicating a competing degree of itinerancy—the movement of electrons in a material. The researchers observed that the $e_g$ state, one of the d-electron states in iron, exhibits strong temperature-driven non-Fermi-liquid behavior near the Curie temperature (Tc), the temperature at which a ferromagnetic material loses its magnetization.
The study reveals that a high-temperature orbital-selective loss of coherence leads to an orbital-selective collapse of magnetization at Tc. This suggests that the ferromagnetic phase of α-Fe is characterized by strong correlation- and temperature-dependent spectral features. Understanding these properties can be crucial for developing advanced magnetic materials for energy applications, such as more efficient transformers, generators, and magnetic storage devices.
The researchers also obtained Coulomb interaction parameters by systematically employing various schemes in cRPA, providing a comprehensive understanding of the electronic interactions in α-Fe. This detailed investigation of the magnetic and spectral properties of α-Fe contributes to the broader field of materials science and could pave the way for innovations in the energy sector.
In summary, the study by Verma, Bhardwaj, and Pandey offers valuable insights into the electronic structure and magnetic properties of α-Fe, highlighting the importance of temperature and electronic correlations. These findings could have practical applications in the development of advanced magnetic materials for energy technologies, ultimately contributing to more efficient and sustainable energy solutions.
This article is based on research available at arXiv.