Quantized Conductance and Large g-Factor Anisotropy in InSb Quantum Point Contacts

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Information Science

Background:

• Indium antimonide (InSb) is crucial for Majorana fermion research due to its strong spin-orbit interaction and large Landé g-factor.
• Quantum wells offer a promising alternative to nanowires for developing hybrid devices to study Majorana fermions.

Purpose of the Study:

• To investigate the potential of InSb/InAlSb quantum wells as a platform for exploring Majorana fermions.
• To characterize the electronic properties of quantum point contact devices in these hybrid structures.

Main Methods:

• Fabrication and characterization of quantum point contact devices in InSb/InAlSb quantum wells.
• Application of a rotating magnetic field to probe g-factor anisotropy.
• Analysis of subband crossings and magnetic depopulation to determine electron effective mass.

Main Results:

• Observed pronounced conductance quantization in the quantum point contact devices.
• Measured a large in-plane (g₁ = 26) and out-of-plane (g₁ = 52) g-factor anisotropy.
• Investigated spin-dependent subband crossings and extracted the electron effective mass.

Conclusions:

• InSb/InAlSb quantum wells demonstrate significant potential for advancing Majorana fermion research.
• The observed properties, including g-factor anisotropy and conductance quantization, highlight the suitability of these devices for fundamental quantum studies.