Edge-State Selective Measurement of Dispersions in the Quantum Hall Regime

Area of Science:

• Condensed matter physics
• Quantum mechanics
• Materials science

Background:

• Quantum Hall edge states are crucial for understanding quantum phenomena but are challenging to study individually.
• Multiple coexisting edge states often overlap spatially, complicating their analysis.

Purpose of the Study:

• To develop a method for individually resolving and characterizing quantum Hall edge states.
• To extract the energy dispersions of these edge states.
• To measure edge state velocities across varying magnetic fields and densities.

Main Methods:

• Utilized momentum-resolved tunneling spectroscopy between a quantum well and a quantum wire.
• Employed momentum and energy-selective tunneling to differentiate overlapping edge states.

Main Results:

• Successfully extracted the dispersions of individual quantum Hall edge states.
• Measured edge state velocities over a wide range of magnetic fields and densities.
• Obtained results in excellent agreement with the hard wall model.

Conclusions:

• Momentum-resolved tunneling spectroscopy is an effective technique for individually probing quantum Hall edge states.
• This method provides accurate measurements of edge state velocities.
• The technique lays the foundation for future selective spectroscopy on quantum materials.