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Research Highlight | Center for Nanoscale Materials

Stress in the quantum world: Elastic distortions in GaAs quantum dots

In a study published in Nano Letters, researchers found that stress induced by metal electrodes directly impacts the ability to control positions of potential minima where quantum dots form and the coupling between neighboring quantum dots.

Scientific Achievement

Combining X-ray nanodiffraction with dynamical X-ray diffraction modeling reveals buried strain in quantum devices formed at interfaces in a thin-film hetero-structure, without a need for sectioning the sample.

Significance and Impact

Elastic distortions in active areas of GaAs/AlGaAs heterostructures will impact their use in quantum electronics based on coupled quantum dots.

Research Details

  • Nanoscale variations of stress in GaAs heterostructures change the potential energy landscape of the two-dimensional electron gas limiting the control of quantum devices.
  • The structure was measured without perturbing the stress state by using a new combination of x-ray dynamical diffraction modeling and nanoscale scanning x-ray diffraction microscopy (nano-SXDM) at the CNM / APS Hard X-ray Nanoprobe.


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Work was performed in part at the Center for Nanoscale Materials and Advanced Photon Source.

Elastic distortion within electrostatically defined quantum dots (top) was observed using a combination of new dynamical diffraction modeling methods and nano-focused X-ray diffraction (bottom).

About Argonne’s Center for Nanoscale Materials
The Center for Nanoscale Materials is one of the five DOE Nanoscale Science Research Centers, premier national user facilities for interdisciplinary research at the nanoscale supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE’s Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge, Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit https://​sci​ence​.osti​.gov/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​/​U​s​e​r​-​F​a​c​i​l​i​t​i​e​s​-​a​t​-​a​-​G​lance.

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The U.S. Department of Energy’s Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit https://​ener​gy​.gov/​s​c​ience.