Fermi arcs

Definition

Fermi arcs are surface states that appear in certain topological semimetals, characterized by an open curve on the Fermi surface rather than the closed loops typical in conventional metals. These arcs arise due to the nontrivial topology of the electronic band structure, indicating the presence of Weyl points, which are locations in momentum space where the conduction and valence bands touch. Fermi arcs reveal important information about the nature of surface states and their relation to bulk properties, showcasing unique electronic behaviors in topological materials.

5 Must Know Facts For Your Next Test

1. Fermi arcs are typically observed on the surface of Weyl semimetals and provide evidence for the existence of Weyl points in the bulk material.
2. The length and shape of Fermi arcs can change depending on external factors such as magnetic field strength or chemical potential, making them sensitive probes of electronic properties.
3. In contrast to conventional metals, where Fermi surfaces are closed loops, Fermi arcs demonstrate an open structure, indicating their unique topological characteristics.
4. Fermi arcs can lead to unusual transport phenomena, such as anomalous Hall effects and enhanced surface conductivity compared to bulk properties.
5. The study of Fermi arcs has significant implications for understanding quantum phase transitions and could contribute to advances in next-generation electronic devices.

Review Questions

• How do Fermi arcs differ from conventional Fermi surfaces found in typical metals?
  • Fermi arcs differ from conventional Fermi surfaces primarily in their structure; while typical metals feature closed loops representing the Fermi surface, Fermi arcs are characterized by open curves. This open nature reflects the nontrivial topology present in materials like Weyl semimetals, where Weyl points indicate a special electronic state. The presence of these open surfaces suggests unique electronic behaviors and connectivity between surface states and bulk properties, enhancing our understanding of topological materials.
• Discuss the relationship between Fermi arcs and Weyl points in topological semimetals.
  • Fermi arcs are closely linked to Weyl points found in topological semimetals. The Weyl points serve as locations in momentum space where conduction and valence bands intersect, leading to unique surface states represented by Fermi arcs. The existence of these arcs provides experimental evidence for Weyl points and highlights how surface states can be influenced by bulk properties, showcasing the fundamental connection between the topology of a material's electronic structure and its observable physical characteristics.
• Evaluate how the presence of Fermi arcs could impact future technological applications in electronics or materials science.
  • The presence of Fermi arcs offers exciting possibilities for future technologies due to their unique electronic properties. For instance, they can lead to enhanced conductivity and novel transport phenomena such as unusual Hall effects, which might be harnessed for developing more efficient electronic devices. Additionally, understanding Fermi arcs contributes to advancing quantum computing technologies by leveraging topologically protected states that could improve error resistance. As research continues into materials exhibiting these properties, new applications may emerge that revolutionize our approach to electronics and materials science.

Related terms

Weyl semimetals: A class of topological semimetals that host Weyl points, where the conduction and valence bands touch, resulting in exotic electronic properties.

Topological insulators: Materials that behave as insulators in their bulk but have conducting states on their surfaces due to nontrivial topological order.

Dirac cones: The conical shape of the energy dispersion relation near the Dirac points in materials like graphene, which is related to massless charge carriers.