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Electron-electron interactions in low-dimensional Si:P delta layers



Joseph Hagmann, Xiqiao Wang, Ranjit Kashid, Pradeep Namboodiri, Jonathan Wyrick, Scott W. Schmucker, Michael Stewart, Richard M. Silver, Curt A. Richter


Key to producing quantum computing devices based on the atomistic placement of dopants in silicon by scanning tunneling microscope (STM) lithography is the formation of embedded highly doped Si:P delta layers (δ-layers). This study investigates the transport behavior and the electron-electron interaction (EEI) physics in the highly doped regions of embedded Si:P-based devices by means of self-consistent magnetotransport measurements. From careful magnetotransport study at low temperature and analysis of the weak localization (WL) signal, we extract parameters associated with the electronic transport that offer a meaningful quantitative characterization of δ-layer quality and dopant diffusion. In addition, by examining EEI behaviors in a set of samples with embedded Si:P delta layers produced with different PH3 exposure procedures prior to Si encapsulation, we show that the charge carriers behave as 2DEGs in embedded Si:P δ-layers in samples grown with a locking layer to bolster confinement of the dopants, while samples grown without a locking layer demonstrate several signatures of transport and EEI in a 3D system. This work establishes the relationship between δ-layer confinement and EEI on screening lengths, the understanding of which will lead to improvements in the control of electrostatic gating of and tunneling transport through Si:P single atom transistors.
Physical Review B


quantum, quantum transport, nanoelectronics, silicon, doping, weak-localization


Hagmann, J. , Wang, X. , Kashid, R. , Namboodiri, P. , Wyrick, J. , Schmucker, S. , Stewart, M. , Silver, R. and Richter, C. (2020), Electron-electron interactions in low-dimensional Si:P delta layers, Physical Review B, [online],, (Accessed July 20, 2024)


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Created June 14, 2020, Updated October 12, 2021