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Donor-bound-exciton strain microscopy in silicon devices
Authors:
Pierandrea Conti,
Siddharth Dhomkar,
Philipp Ross,
John Mansir,
John J. L. Morton
Abstract:
We explore the effects of stress on silicon donor bound exciton ($\mathrm{D^0X}$) transitions in bulk silicon and in microfabricated silicon devices. We first study $\mathrm{D^0X}$ transitions in an isotopically purified silicon-28 bulk doped sample under controlled uniaxial stress, confirming the validity of existing models in the low strain ($\lesssim 10^{-5}$) regime. We then demonstrate the lo…
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We explore the effects of stress on silicon donor bound exciton ($\mathrm{D^0X}$) transitions in bulk silicon and in microfabricated silicon devices. We first study $\mathrm{D^0X}$ transitions in an isotopically purified silicon-28 bulk doped sample under controlled uniaxial stress, confirming the validity of existing models in the low strain ($\lesssim 10^{-5}$) regime. We then demonstrate the localised photoconductive detection of a few thousand donors illuminated by a 1078 nm resonant laser with $4~\mathrm{μm}$ spot focused on a microfabricated device consisting of an implanted phosphorus layer between a pair of metallic contacts. We observe local variations in the strained exciton peak splitting from $10~\mathrm{μeV}$ to $200~\mathrm{μeV}$, and obtain scanning microscopy stress maps in good agreement with finite-element-model thermal stress simulations. Our results suggest a potential use of donor bound excitons for in-situ stress sensing, and demonstrate pathways for the miniaturisation of $\mathrm{D^0X}$ photoconductive detection.
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Submitted 30 August, 2024;
originally announced August 2024.
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Linear hyperfine tuning of donor spins in silicon using hydrostatic strain
Authors:
John Mansir,
Pierandrea Conti,
Zaiping Zeng,
Jarryd J. Pla,
Patrice Bertet,
Michael W. Swift,
Chris G. Van de Walle,
Mike L. W. Thewalt,
Benoit Sklenard,
Yann-Michel Niquet,
John J. L. Morton
Abstract:
We experimentally study the coupling of Group V donor spins in silicon to mechanical strain, and measure strain-induced frequency shifts which are linear in strain, in contrast to the quadratic dependence predicted by the valley repopulation model (VRM), and therefore orders of magnitude greater than that predicted by the VRM for small strains $|\varepsilon| < 10^{-5}$. Through both tight-binding…
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We experimentally study the coupling of Group V donor spins in silicon to mechanical strain, and measure strain-induced frequency shifts which are linear in strain, in contrast to the quadratic dependence predicted by the valley repopulation model (VRM), and therefore orders of magnitude greater than that predicted by the VRM for small strains $|\varepsilon| < 10^{-5}$. Through both tight-binding and first principles calculations we find that these shifts arise from a linear tuning of the donor hyperfine interaction term by the hydrostatic component of strain and achieve semi-quantitative agreement with the experimental values. Our results provide a framework for making quantitative predictions of donor spins in silicon nanostructures, such as those being used to develop silicon-based quantum processors and memories. The strong spin-strain coupling we measure (up to 150~GHz per strain, for Bi-donors in Si), offers a method for donor spin tuning --- shifting Bi donor electron spins by over a linewidth with a hydrostatic strain of order $10^{-6}$ --- as well as opportunities for coupling to mechanical resonators.
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Submitted 23 March, 2018; v1 submitted 2 October, 2017;
originally announced October 2017.
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Cantori and dynamical localization in the Bunimovich Stadium
Authors:
Fausto Borgonovi,
Paolo Conti,
Daniela Rebuzzi,
Bambi Hu,
Baowen Li
Abstract:
Classical and quantum properties of the Bunimovich stadium in the diffusive regime are reviewed. In particular, the quantum properties are directly investigated using an approximate quantum map. Different localized regimes are found, namely, perturbative, quasi-integrable (due to classical Cantori), dynamical and ergodic.
Classical and quantum properties of the Bunimovich stadium in the diffusive regime are reviewed. In particular, the quantum properties are directly investigated using an approximate quantum map. Different localized regimes are found, namely, perturbative, quasi-integrable (due to classical Cantori), dynamical and ergodic.
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Submitted 22 July, 1998;
originally announced July 1998.