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Transport in 2D Electron Gas

Eran Maniv  
Instructor of the 2DEG experiment

 

Room: Kaplun Basement 013

Telephone.gif Phone: 03-640-8286

Em_anm.gif Email: eranmaniv@mail.tau.ac.il


 

Contents:

  1. Introduction
  2. Topics of the experiment
  3. How to prepare for the experiment?
  4. The experimental schedule
  5. Auxiliary Literature
  6. Links

 

Introduction:

The rapid growth of the science of nanostructures is having a considerable impact on physics, because these structures exhibit qualitatively new phenomena, and on electrical engineering, because they have applications to the electronic devices of the future. The transport phenomena in two dimensional electron gas (2DEG) are the main part of the nanostructures' science and solid-state physics. Two dimensional electron gas is typically present in a modulation-doped GaAs/AlGaAs heterostructure at the interface between GaAs and AlGaAs layers. These heterostructures are fabricated using Molecular Beam Epitaxy (MBE) growth procedure.

 

Topics of the experiment:

  • Low temperature investigations of transport properties of 2DEG:
  1. Classical Hall effect
  2. Integer Quantum Hall effect
  3. Shubnikov - de Haas ocsillations
  • Study of the basic principles of the lock-in technique for transport measurements.

 

How to prepare for the experiment?

  1. Read the basic literature: 
    1. C. Weisbuch, B. Vinter, Quantum Semiconductor Structures, p. 11-15, 20-22, 38-39, 123-139.
    2. T. Chakraborty, P.Pietil inen, The Quantum Hall Effects, p. 1-11.
    3. J. H. Scofield, "A Frequency-Domain Description of a Loch-in Amplifier", American Journal of Physics, 62 (2), 129-133 (1994).
    4. 2DEG Experiment Instructions
  2. Study the experimental equipment
    1. Lock-in amplifier SR-510 Stanford Research Systems.
    2. Temperature controller Lake Shore Model 331.
    3. Keithley 2400 SourceMeter .
  1. Learn the experiment's schedule.
  2. Make sure that you understand the experimental setup (in the experiment's instructions).
  3. Study the preparatory questions  (in the experiment's instructions).

 

 

The experimental schedule:

  1. Written exam - Approximately one hour.
  2. Learning the experimental apparatus and measurements configurations.
  3. Resistance Vs. Temperature of the sample will be measured during cooldown to 4.2K.
  4. Variation of the longitudinal resistance and the Hall effect in the range of the magnetic field between 0 to 5 Tesla will be measured at 4.2 K and at zero gate bias.
  5. Longitudinal and Hall resistance will be measured versus gate voltage at constant low magnetic field value.
  6. Analysis of the data (described in the experiment's instructions).
  7. Completing necessary measurements if needed.

 

Auxiliary Literature:

1. Ch. Kittel, Introduction to Solid State Physics, 6th edition, p. 128-150, 160-163, 539-544.

2. N.W. Ashcroft and N.D. Mermin, Solid State Physics, p. 2-15, 270-274, 323-324, 523-526.

3. P.T. Colerdge, "Small angle scattering in two-dimensional electron gases", Phys.Rev.B., 44, 3793, 1991.

 

Links:

  1. Introduction to the Hall effects (both classical and quantum)
  2. Introduction to the Lock-in technique 

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