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Updated: Oct 5, 2025
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Published on: July 20, 2022
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Suppression of impurity magnetization by the saddle points
Xue-Yu Tang1, Yun Zhang2, Kai-He Ding1,3
1Department of Physics and Electronic Science, Changsha University of Science and Technology, Changsha 410004, People's Republic of China.
Summary
Investigating magnetic states in semi-Dirac systems reveals saddle point energy (SPE) significantly impacts impurity magnetization. Minimum magnetization occurs at SPE matching impurity energy, with SPE influencing local magnetic moments.
Area of Science:
- Condensed matter physics
- Materials science
- Quantum magnetism
Background:
- Semi-Dirac materials exhibit unique electronic properties due to their band structure.
- Localized magnetic states in impurities can significantly alter material properties.
- Saddle points (SP) in band structures can lead to novel phenomena.
Purpose of the Study:
- To investigate the localized magnetic states of an impurity within a semi-Dirac-like system featuring a saddle point (SP).
- To understand how varying the saddle point energy (SPE) affects impurity magnetization and magnetic moment.
- To explore the interplay between the SP, Coulomb interaction, and local magnetization.
Main Methods:
- Theoretical study of localized magnetic states.
- Analysis of impurity magnetization and magnetic moment as a function of saddle point energy.
- Investigation of the density of states asymmetry induced by the saddle point.
Main Results:
- Impurity magnetization region diminishes with increasing SPE, reaching a minimum when SPE equals impurity energy.
- Further increase in SPE leads to a rapid expansion of the impurity magnetization region.
- A notable decrease in the impurity magnetic moment is observed near the impurity energy due to SP-induced mitigation of density of states asymmetry.
Conclusions:
- The saddle point energy critically controls the spatial extent and magnitude of localized magnetic states around an impurity in semi-Dirac systems.
- The suppression of magnetization near the impurity energy is attributed to the saddle point's effect on electronic state asymmetry.
- The presence and energy of the saddle point, along with Coulomb interactions, dictate the complex magnetic behavior of impurities.
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