Weyl semimetal in a topological insulator multilayer

Area of Science:

• Condensed Matter Physics
• Materials Science
• Topological Materials

Background:

• Topological insulators exhibit unique electronic properties protected by topology.
• Weyl semimetals are exotic states of matter with potential applications in electronics.
• Achieving 3D Weyl semimetal phases in realistic material systems remains a challenge.

Purpose of the Study:

• To propose and theoretically realize a simple three-dimensional (3D) Weyl semimetal phase.
• To investigate the electronic band structure and phase diagram of a proposed multilayer system.
• To explore the unique transport properties and topological features of the Weyl semimetal phase.

Main Methods:

• Utilizing a multilayer structure composed of magnetically doped 3D topological insulator thin films and ordinary-insulator spacers.
• Analyzing the electronic band structure to identify Dirac nodes and topological phase transitions.
• Investigating the anomalous Hall conductivity and dc conductivity at finite temperatures.

Main Results:

• A simple 3D Weyl semimetal phase with two Dirac nodes of opposite chirality was identified.
• The Weyl semimetal phase was found to be an intermediate phase between an ordinary insulator and a 3D quantum anomalous Hall insulator.
• The system exhibits a finite anomalous Hall conductivity, chiral edge states, and a nonzero dc conductivity at zero temperature.

Conclusions:

• The proposed multilayer structure provides a viable route for realizing 3D Weyl semimetals.
• The discovered Weyl semimetal phase possesses unique topological and transport properties.
• This work opens avenues for exploring novel quantum phenomena and potential device applications.