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Title: Effective g factor of low-density two-dimensional holes in a Ge quantum well

Abstract

Here we report the measurements of the effective g factor of low-density two-dimensional holes in a Ge quantum well. Using the temperature dependence of the Shubnikov-de Haas oscillations, we extract the effective g factor in a magnetic field perpendicular to the sample surface. Very large values of the effective g factor, ranging from ~13 to ~28, are observed in the density range of 1.4×10 10 cm -2– 1.4×10 11 cm -2. When the magnetic field is oriented parallel to the sample surface, the effective g factor is obtained from a protrusion in the magneto-resistance data that signify full spin polarization. In the latter orientation, a small effective g factor, ~1.3-1.4, is measured in the density range of 1.5×10 10 cm -2–2×10 10 cm -2. Finally, this very strong anisotropy is consistent with theoretical predictions and previous measurements in other 2D hole systems, such as InGaAs and GaSb.

Authors:
ORCiD logo [1];  [2];  [3];  [3];  [3];  [3]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Center for Integrated Nanotechnologies
  3. National Taiwan Univ., Taipei (Taiwan). Dept. of Electrical Engineering and Graduate Inst. of Electronic Engineering; National Nano Device Lab., Hsinchu (Taiwan)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Science Foundation (NSF); Ministry of Science and Technology
OSTI Identifier:
1398779
Report Number(s):
SAND-2017-9871J
Journal ID: ISSN 0003-6951; 656977
Grant/Contract Number:
AC04-94AL85000; NA0003525
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 111; Journal Issue: 10; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; G factor; Quantum wells; Magnetic ordering; Semiconductors; Spintronics

Citation Formats

Lu, T. M., Harris, C. T., Huang, S. -H., Chuang, Y., Li, J. -Y., and Liu, C. W. Effective g factor of low-density two-dimensional holes in a Ge quantum well. United States: N. p., 2017. Web. doi:10.1063/1.4990569.
Lu, T. M., Harris, C. T., Huang, S. -H., Chuang, Y., Li, J. -Y., & Liu, C. W. Effective g factor of low-density two-dimensional holes in a Ge quantum well. United States. doi:10.1063/1.4990569.
Lu, T. M., Harris, C. T., Huang, S. -H., Chuang, Y., Li, J. -Y., and Liu, C. W. 2017. "Effective g factor of low-density two-dimensional holes in a Ge quantum well". United States. doi:10.1063/1.4990569.
@article{osti_1398779,
title = {Effective g factor of low-density two-dimensional holes in a Ge quantum well},
author = {Lu, T. M. and Harris, C. T. and Huang, S. -H. and Chuang, Y. and Li, J. -Y. and Liu, C. W.},
abstractNote = {Here we report the measurements of the effective g factor of low-density two-dimensional holes in a Ge quantum well. Using the temperature dependence of the Shubnikov-de Haas oscillations, we extract the effective g factor in a magnetic field perpendicular to the sample surface. Very large values of the effective g factor, ranging from ~13 to ~28, are observed in the density range of 1.4×1010 cm-2– 1.4×1011 cm-2. When the magnetic field is oriented parallel to the sample surface, the effective g factor is obtained from a protrusion in the magneto-resistance data that signify full spin polarization. In the latter orientation, a small effective g factor, ~1.3-1.4, is measured in the density range of 1.5×1010 cm-2–2×1010 cm-2. Finally, this very strong anisotropy is consistent with theoretical predictions and previous measurements in other 2D hole systems, such as InGaAs and GaSb.},
doi = {10.1063/1.4990569},
journal = {Applied Physics Letters},
number = 10,
volume = 111,
place = {United States},
year = 2017,
month = 9
}

Journal Article:
Free Publicly Available Full Text
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  • High-mobility two-dimensional (2D) holes residing in a Ge quantum well are a new electronic system with potentials in quantum computing and spintronics. Since for any electronic material, the effective mass and the g factor are two fundamental material parameters that determine the material response to electric and magnetic fields, measuring these two parameters in this material system is thus an important task that needs to be completed urgently. Because of the quantum confinement in the crystal growth direction (z), the biaxial strain of epitaxial Ge on SiGe, and the valance band nature, both the effective mass and the g factormore » can show very strong anisotropy. In particular, the in-plane g factor (g ip) can be vanishingly small while the perpendicular g factor (g z) can be much larger than 2. Here we report the measurement of g ip at very low hole densities using in-plane magneto-resistance measurement performed at the NHMFL.« less
  • Cyclotron resonance of the two-dimensional hole gas (2DHG) in the strained-layer quantum well structure of In/sub 0.20/Ga/sub 0.80/As/GaAs is observed in far-infrared transmission measurements made at 4.2 K. The cyclotron mass of the 2DHG in the In/sub 0.20/Ga/sub 0.80/As channel is (0.191/plus minus/0.008)/ital m//sub /ital e// for a 2D hole density /ital p//sub 2D/ =8.5/times/10/sup 11//cm/sup 2/.
  • The change in confinement factor with carrier density has been proposed to explain the gain overshoot and near field displacement in ultrafast pump-probe experiments on quantum-well optical amplifiers. Here a new mechanism is described that may reduce the effective differential gain due to the modulation of the confinement factor with carrier density in quantum-well lasers. This mechanism may limit modulation bandwidth for quantum-well lasers with high threshold carrier density and narrow confining layer.
  • Quantum Hall measurement of two-dimensional high-mobility [μ∼2×10{sup 6} cm{sup 2}/(V·s)] hole systems confined in a 20 nm wide (100)-GaAs quantum well have been performed for charge densities between 4 and 5 × 10{sup 10} cm{sup −2} in a temperature range of 10–160 mK. The Fourier analysis of the Shubnikov-de Haas (SdH) oscillations of the magnetoresistance vs. the inverse of the magnetic field 1/B reveals a single peak, indicating a degenerate heavy hole (HH) band. The hole density p=(e/h)·f agrees with the Hall measurement result within 3%. The HH band degeneracy is understood through the diminishing spin-orbit interaction due to the low charge density and themore » nearly symmetric confinement. SdH oscillations fitted for 0.08 T ≤ B ≤ 0.24 T to the Dingle parameters yield an effective mass between 0.30 and 0.50 m{sub e} in good agreement with previous cyclotron resonance results.« less