Controllable p-n junctions in three-dimensional Dirac semimetal Cd₃As₂ nanowires.

Area of Science:

• Condensed matter physics
• Materials science
• Nanotechnology

Background:

• Three-dimensional Dirac semimetals (DSMs) possess unique electronic properties.
• Cd3As2 is a prominent DSM material with potential for electronic applications.
• Controlling charge carriers in semimetals is crucial for device fabrication.

Purpose of the Study:

• To demonstrate a controllable p-n junction in a Cd3As2 nanowire.
• To investigate the electronic transport properties under gate voltage and magnetic fields.
• To explore the potential for quantum devices based on DSM nanowires.

Main Methods:

• Fabrication of a Cd3As2 nanowire device with two recessed bottom gates.
• Electrical transport measurements under varying gate voltages and perpendicular magnetic fields.
• Analysis of conductance regimes and quantum phenomena.

Main Results:

• Achieved four distinct conductance regimes (unipolar and bipolar) by tuning gate voltages, indicating controllable p-n junction formation.
• Observed a drastic decrease in conductance in p-n junction regimes under perpendicular magnetic fields.
• Demonstrated quantum dot behavior in p-n junction regimes and conductance plateaus in the n-n regime at high magnetic fields.

Conclusions:

• Ambipolar tunability of DSM nanowires is feasible.
• Cd3As2 nanowires can be utilized to create quantum devices.
• The findings pave the way for novel quantum dots and electron optics applications.