Suppressing Andreev Bound State Zero Bias Peaks Using a Strongly Dissipative Lead

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Computing

Background:

• Hybrid semiconductor-superconductor nanowires are theoretical platforms for hosting Majorana zero modes.
• Majorana zero modes are predicted to manifest as zero-bias peaks (ZBPs) in tunneling conductance measurements.
• Andreev bound states can also produce ZBPs, complicating the unambiguous identification of Majorana modes.

Purpose of the Study:

• To experimentally investigate methods for distinguishing Majorana zero modes from Andreev bound states.
• To demonstrate the suppression of Andreev bound state-induced ZBPs using environmental Coulomb blockade.
• To provide a new experimental technique for advancing Majorana searches.

Main Methods:

• Fabrication of InAs-Al hybrid nanowire devices.
• Integration of a strongly resistive normal lead into the device architecture.
• Measurement of tunneling conductance to observe zero-bias peak (ZBP) suppression.

Main Results:

• Demonstrated the suppression of most Andreev bound state-induced ZBPs via environmental Coulomb blockade.
• Showcased the effectiveness of a resistive lead in mitigating spurious ZBP signals.
• Provided the first experimental validation of dissipative interaction effects on Andreev bound states.

Conclusions:

• Environmental Coulomb blockade offers a viable strategy to suppress Andreev bound states in hybrid nanowires.
• This technique can serve as a crucial filter for narrowing down the phase diagram in Majorana searches.
• The findings pave the way for more reliable experimental detection of Majorana zero modes.