Magnetotransport Properties of Shallow Quantum Well Structures for Spintronic Application

Abstract

Spintronic devices manipulate, generate, and detect spin currents rather than the charge currents found in electronic devices. This requires the materialsemployed to have large spin-orbit coupling and excellent semiconducting properties. This project focused on n-doped InAlSb/InAs/AlGaSbheterostructures which show promise in spintronic applications. These materials have an InAs quantum well near the surface for easy injection anddetection of current and have been optimized to have high electron mobility at room temperature. This project investigated the effect of the well surfaceproximity on the semiconducting and the spin-orbit properties of these materials to establish their potential for spintronic applications. To this end, wemeasured and evaluated competing electron transport mechanisms present in these shallow wells and responsible for the observed behaviors.The sample heterostuctures were fabricated in Hall bars and their sheet and Hall resistance in variable magnetic field, temperature, and illuminationconditions, with wavelengths of 400nm up to 1300nm were measured. We then analyzed the Shubnikov-de Haas oscillations and the Halleffect to extract the semiconducting and spin-orbit properties of these structures. The results arecompared and contrasted with the properties of a deep-channel InAs sample with excellent spinorbitcoupling properties. We find that the carrier concentration of the shallow channels increasesunder infrared illumination, but decreases when further decreasing the wavelength. We also finda general increase in the effective mass of the samples with the carrier concentration. Lastly, wefind that the shallow-well samples do not exhibit observable spin orbit coupling despite excellentsemiconducting properties. We conclude that small quantum scattering times make resolving thespin-split populations difficult.

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Document Details

Document Type
Technical Report
Publication Date
May 21, 2018
Accession Number
AD1054394

Entities

People

  • Benjamin R. Dunphy

Organizations

  • United States Naval Academy

Tags

Communities of Interest

  • Advanced Electronics

DTIC Thesaurus Topics

  • Band Gaps
  • Band Structures
  • Charge Carriers
  • Conduction Bands
  • Crystal Lattices
  • Digital Data
  • Electric Fields
  • Electron Gas
  • Electron Mobility
  • Electrons
  • Energy Bands
  • Energy Gaps
  • Field Effect Transistors
  • Free Electrons
  • Heterojunctions
  • Magnetic Fields
  • Materials
  • Materials Science
  • Quantum Properties
  • Quantum Wells
  • Scattering
  • Semiconductors
  • Solid State Physics
  • Transport Properties
  • Two Dimensional
  • United States Naval Academy

Fields of Study

  • Materials science

Readers

  • Materials Science.
  • Quantum Dot Semiconductor Device Photonics and Graphene Optoelectronic Materials and THz Physics.

Technology Areas

  • Microelectronics
  • Quantum Computing
  • Quantum Science - Quantum Dots
  • Space
  • Space - Hall-Effect Thruster