SiGe-based Quantum Electronic Devices

Tzu-Ming Lu, Ph.D.
Sandia National Laboratories, New Mexico

One of the building blocks of today’s digital technology is two-dimensional electrons in a Si metal-oxide-semiconductor field-effect transistor. These low-dimensional electrons may play an equally essential role in future computing paradigms. SiGe heterostructures hosting low-dimensional electrons/holes have recently emerged as an important material platform for future quantum electronics and spintronics. In this talk, I will first review the fabrication and device operation of SiGe heterostructure field-effect transistors with mobilities as high as 10⁵ – 10⁶ cm²/Vs and then present some interesting quantum phenomena we observe in two-dimensional electron/hole systems in these high-mobility devices, including tunneling-limited non-equilibrium charge distributions, interlayer coherence between two coupled electron layers, and a gate-controlled quantum Hall ferromagnetic transition. Paths toward creating Majorana fermions in SiGe-based materials using the quantum Hall ferromagnetic transition and nanomagnet arrays will be discussed.

Acknowledgements
This work at Sandia National Laboratories has been supported by the Division of Materials Sciences and Engineering, Office of Basic Energy Sciences, US Department of Energy (DOE) and the Laboratory Directed Research and Development Program. This work was performed, in part, at the Center for Integrated Nanotechnologies, a US DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International, Inc., for the US Department of Energy’s National Nuclear Security Administration under Contract No. DE-NA-0003525.

About the Speaker

Tzu-Ming Lu received his B.S. from National Taiwan University in 2004 and his Ph.D. from Princeton University in 2011. He studied quantum phenomena associated with low-dimensional electron systems for his thesis. After graduate school, he joined Sandia National Laboratories as a Postdoc, studying silicon-based spin qubits. He is currently a Senior Member of Technical Staff at Sandia National Laboratories. His research topics include spin-based quantum computing, spin-orbit interactions, and quantum behavior of nanoscale structures. He is also a Center of Integrated Nanotechnologies (CINT) scientist, supporting user projects on quantum information science.