Disentangling phonon and impurity interactions in delta-doped Si(001)
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We present a study of the phonon and impurity interactions in a shallow two dimensional electron gas formed in Si(001). A highly conductive ultra-narrow n-type dopant delta-layer, which serves as a platform for quantum computation architecture, is formed and studied by angle resolved photoemission spectroscopy (ARPES) and temperature dependent nanoscale 4-point probe (4PP). The bandstructure of the delta-layer state is both measured and simulated. At 100 K, good agreement is only achieved by including interactions; electron-impurity scattering (W-0 = 56 to 61 meV); and electron-phonon coupling (lambda = 0.14 +/- 0.04). These results are shown to be consistent with temperature dependent 4PP resistance measurements which indicate that at 100 K, approximate to 7/8 of the measured resistance is due to impurity scattering with the remaining 1/8 coming from phonon interactions. In both resistance and bandstructure measurements, the impurity contribution exhibits a variability of approximate to 9% for nominally identical samples. The combination of ARPES and 4PP affords a thorough insight into the relevant contributions to electrical resistance in reduced dimensionality electronic platforms. (C) 2014 AIP Publishing LLC.