Magnetization jump in one dimensional J - Q ₂ model with anisotropic exchange

Area of Science:

• Condensed matter physics
• Quantum magnetism
• Many-body systems

Background:

• The J-Q2 model describes interacting quantum spins in one dimension.
• Understanding magnetization processes is key to quantum materials.
• XXZ anisotropy and external magnetic fields introduce complex behaviors.

Purpose of the Study:

• Investigate the adiabatic magnetization process in the 1D J-Q2 model.
• Map the magnetization phase diagram under varying XXZ anisotropy (g) and magnetic field (h).
• Identify the mechanisms behind magnetization jumps.

Main Methods:

• Density Matrix Renormalization Group (DMRG) for accurate ground state calculations.
• Analysis of magnetization curves to identify distinct phases.
• Examination of energy per magnon and correlation functions.

Main Results:

• A four-phase magnetization diagram was established based on g.
• Magnetization jumps occur for specific g values, originating from magnon condensation and domain formation.
• States before and after jumps exhibit different magnetic ordering (Heisenberg-like vs. antiferromagnetic/Néel).

Conclusions:

• The J-Q2 model exhibits rich magnetic phases and magnetization behaviors.
• Magnon condensation drives quantum phase transitions in this system.
• The interplay of anisotropy and magnetic fields dictates the emergent magnetic order.