Orbital-Selectivity-Induced Robust Quantum Anomalous Hall Effect in Hund's Metals MgFeP

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• High Curie temperature (Tc) ferromagnetic (FM) states and strong spin-orbit coupling (SOC) are crucial for achieving room-temperature quantum anomalous Hall (QAH) effects.
• Developing novel 2D materials with robust FM properties and significant SOC is essential for advancing topological electronic devices.

Purpose of the Study:

• To propose and investigate a new 2D iron-based monolayer, MgFeP, for its potential to host high-temperature QAH effects.
• To explore the electronic and magnetic properties of MgFeP, focusing on its multiorbital nature and the role of orbital-selective Mott phase (OSMP).

Main Methods:

• First-principles calculations were employed to investigate the structural, electronic, and magnetic properties of the 2D MgFeP monolayer.
• The study analyzed the multiorbital electronic structure, identifying localized and itinerant orbitals contributing to the material's unique phase.
• The impact of spin-orbit coupling (SOC) on the electronic band structure and the emergence of the QAH state was examined.

Main Results:

• MgFeP exhibits a high ferromagnetic Curie temperature (Tc) of approximately 1525 K and excellent structural stability.
• The material displays a unique multiorbital electronic structure, characterized as a Hund's metal in an orbital-selective Mott phase (OSMP).
• This OSMP facilitates a double exchange mechanism, explaining the high Tc, and enables a transition to a QAH insulator upon inclusion of SOC, with an enlarged band gap of 137 meV.

Conclusions:

• MgFeP is a promising 2D material for high-performance quantum topological electronic devices due to its high Tc and tunable QAH properties.
• Hund's metals exhibiting OSMP represent a viable material platform for realizing robust room-temperature QAH effects.
• Leveraging orbital selectivity offers a pathway to significantly enhance the QAH band gap, crucial for practical applications.