Tailoring Robust Quantum Anomalous Hall Effect via Entropy-Engineering.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Materials

Background:

• Quantum materials with tailored properties are crucial for advanced applications.
• The quantum anomalous Hall (QAH) effect is a key phenomenon in topological materials.
• Achieving a robust QAH effect with gapped bulk bands is a significant challenge.

Purpose of the Study:

• To propose a novel design concept for a robust QAH effect using entropy engineering in 2D magnets.
• To investigate the impact of configurational entropy on the electronic band structure of monolayer VCl3.
• To demonstrate the transformation of a Dirac half-metal into a state supporting a robust QAH phase.

Main Methods:

• Utilizing first-principles calculations to study monolayer transition metal trihalide VCl3.
• Manipulating configurational entropy by incorporating various transition-metal cations (Ti, Cr, Fe, Co) into the VCl3 honeycomb structure.
• Analyzing band structure renormalization, including band flattening and energy shifts, due to entropy engineering.

Main Results:

• Entropy engineering breaks in-plane mirror symmetries, inversion, and/or roto-inversion in monolayer VCl3.
• The process transforms the ferromagnetic Dirac half-metal into a Dirac spin-gapless semiconductor.
• A robust QAH phase with fully gapped bulk band dispersion is achieved, enabling purely topological edge state transport.

Conclusions:

• Configurational entropy engineering provides a viable strategy for designing robust QAH materials.
• This approach facilitates the realization of quantum anomalous Hall effect in 2D magnets.
• The findings pave the way for developing novel quantum devices based on entropy-engineered materials.