Physics Colloquium: (Al, In, Ga) (As, Sb) Quantum Structures by Molecular Beam Expitaxy

Event Details

  • Speaker(s): Zbig Wasilewski
  • Date:
  • Time: 3:30 PM
  • Location: MacN 101

Abstract

In the area of semiconductors and related applications recent advances have been centered around nanoelectronics, nanophotonics and spintronics (including topological insulators), often in the context of quantum computing and cryptography, as well as on expanding range of sensors and light sources, again firmly grounded in quantum physics and nanotechnology. Fundamental to it all is material physics and engineering. Well controlled manipulation of material structure at atomic level is now essential in achieving the desirable properties of nanodevices, were they to be electronic, photonic or spintronic in nature. Molecular Beam Epitaxy (MBE) is arguably the most powerful tool for such nanoengineering. Even though the technology is used presently for broad range of material systems where sub-monolayer control of layer composition is essential, the III/V semiconductors continue to dominate the field from the mainstream production to the frontiers of quantum computing. In this talk I will attempt to excite the audience with the expanse of physics yet to be tapped into using one the most “classical” III-V material system - (Al, In, Ga)(As, Sb). I will illustrate my case with several examples from the most recent advances in quantum devices based on this material system, such THz Quantum Cascade Lasers with record high operating temperature1,2, quantum interferences in few electron lateral multiple dot systems3,4 as well as ultrafast optical control of qubits in vertical self-assembled double dot systems5 grown with so-called In-flush technique.6 A compact overview of MBE technology and its capabilities will be given in the introduction.

References:

  1. Z. R. Wasilewski, \"Molecular Beam Epitaxy Growth of THz Qunatum Cascade Lasers\" in Molecular Beam Epitaxy, edited by M. Hennini (Elsevier, 2012)
  2. S. Fathololoumi, E. Dupont, C. W. I. Chan, Z. R. Wasilewski, S. R. Laframboise, D. Ban, A. Mátyás, C. Jirauschek, Q. Hu, and H. C. Liu, \"Terahertz quantum cascade lasers operating up to ~ 200 K with optimized oscillator strength and improved injection tunneling\", Opt. Express 20, 3866-3876 (2012)
  3.  G. Granger, D. Taubert, C. E. Young, L. Gaudreau, A. Kam, S. A. Studenikin, P. Zawadzki, D. Harbusch, D. Schuh, W. Wegscheider, Z. R. Wasilewski, A. A. Clerk, S. Ludwig, and A. S. Sachrajda, \"Quantum interference and phonon-mediated back-action in lateral quantum-dot circuits\", Nat Phys 8, 522-527 (2012)
  4. L. Gaudreau, G. Granger, A. Kam, G. C. Aers, S. A. Studenikin, P. Zawadzki, M. Pioro-Ladriere, Z. R. Wasilewski, and A. S. Sachrajda, \"Coherent control of three-spin states in a triple quantum dot\", Nat Phys 8, 54-58 (2012)
  5. D. Kim, S. G. Carter, A. Greilich, A. S. Bracker, and D. Gammon, \"Ultrafast optical control of entanglement between two quantum-dot spins\", Nat Phys 7, 223-229 (2011)
  6. Z. R. Wasilewski, S. Fafard, and J. P. McCaffrey, \"Size and shape engineering of vertically stacked self-assembled quantum dots\", J. Cryst. Growth 201-202, 1131-1135 (1999)

Host:

Professor Stefan Kycia