Experimental realization of a three-dimensional Dirac semimetal

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Physics

Background:

• The existence of three-dimensional (3D) Dirac semimetals has been theoretically predicted but experimentally elusive.
• Cadmium arsenide (Cd(3)As(2)) is a material with potential for unique electronic properties.

Purpose of the Study:

• To directly observe the 3D Dirac semimetal phase in cadmium arsenide (Cd(3)As(2)).
• To investigate the electronic structure responsible for Cd(3)As(2)'s high electron mobility.

Main Methods:

• Angle-resolved photoemission spectroscopy (ARPES) was employed for direct observation.
• Analysis focused on identifying specific momentum regions and electronic state dispersions.

Main Results:

• Direct observation of the 3D Dirac semimetal phase in Cd(3)As(2).
• Identification of two momentum regions with narrow, conelike electronic state dispersions, confirming 3D Dirac points.
• The observed electronic structure correlates with Cd(3)As(2)'s exceptionally high bulk electron mobility.

Conclusions:

• The experimental realization of the 3D Dirac semimetal phase in Cd(3)As(2) is confirmed.
• This discovery provides a platform for exploring applications and engineering topological phases, such as Weyl semimetals and quantum spin Hall systems.