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Pauli spin blockade and lifetime-enhanced transport in a Si/SiGe double quantum dot

C. B. Simmons, Teck Seng Koh, Nakul Shaji, Madhu Thalakulam, L. J. Klein, Hua Qin, H. Luo, D. E. Savage, M. G. Lagally, A. J. Rimberg, Robert Joynt, Robert Blick, Mark Friesen, S. N. Coppersmith, and M. A. Eriksson
Phys. Rev. B 82, 245312 – Published 14 December 2010

Abstract

We analyze electron-transport data through a Si/SiGe double quantum dot in terms of spin blockade and lifetime-enhanced transport (LET), which is transport through excited states that is enabled by long spin-relaxation times. We present a series of low-bias voltage measurements showing the sudden appearance of a strong tail of current that we argue is an unambiguous signature of LET appearing when the bias voltage becomes greater than the singlet-triplet splitting for the (2,0) electron state. We present eight independent data sets, four in the forward-bias (spin-blockade) regime and four in the reverse-bias (lifetime-enhanced transport) regime and show that all eight data sets can be fit to one consistent set of parameters. We also perform a detailed analysis of the reverse-bias (LET) regime, using transport rate equations that include both singlet and triplet transport channels. The model also includes the energy-dependent tunneling of electrons across the quantum barriers and resonant and inelastic tunneling effects. In this way, we obtain excellent fits to the experimental data, and we obtain quantitative estimates for the tunneling rates and transport currents throughout the reverse-bias regime. We provide a physical understanding of the different blockade regimes and present detailed predictions for the conditions under which LET may be observed.

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  • Received 31 August 2010

DOI:https://doi.org/10.1103/PhysRevB.82.245312

©2010 The American Physical Society

Authors & Affiliations

C. B. Simmons1, Teck Seng Koh1, Nakul Shaji1, Madhu Thalakulam1, L. J. Klein1, Hua Qin1, H. Luo1, D. E. Savage1, M. G. Lagally1, A. J. Rimberg2, Robert Joynt1, Robert Blick1, Mark Friesen1, S. N. Coppersmith1, and M. A. Eriksson1

  • 1University of Wisconsin–Madison, Madison, Wisconsin 53706, USA
  • 2Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755, USA

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Issue

Vol. 82, Iss. 24 — 15 December 2010

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