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Vacancy-Induced Low-Energy States in Undoped Graphene
Sambuddha Sanyal1, Kedar Damle2, Olexei I Motrunich3
1International Center for Theoretical Sciences, Tata Institute of Fundamental Research, Bengaluru 560089, India.
Physical Review Letters
|September 24, 2016
Summary
Static vacancies in graphene create zero-energy states. Their density depends on vacancy concentration and arrangement, showing a unique divergence and crossover to universal scaling at low energies.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Theoretical Physics
Background:
- Graphene's electronic properties are sensitive to defects.
- Vacancies can significantly alter band structure and electronic states.
Purpose of the Study:
- Investigate the impact of static vacancies on graphene's electronic states.
- Characterize the density of states near the band center.
Main Methods:
- Tight-binding model with nearest-neighbor hopping.
- Analysis of static, randomly placed vacancies in graphene.
- Examination of compensated vacancy configurations and hopping disorder.
Main Results:
- A nonzero density of zero-energy quasiparticle states arises from vacancies.
- The density of states exhibits a Dyson-like divergence at low energies.
- A crossover to modified Gade-Wegner scaling is observed at very low energies.
Conclusions:
- Vacancy concentration and correlations are crucial for zero-energy states.
- The observed electronic behavior deviates from simpler models.
- Understanding these states is key for graphene-based electronic applications.
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