4 research outputs found
Engineering shallow spins in diamond with nitrogen delta-doping
We demonstrate nanometer-precision depth control of nitrogen-vacancy (NV)
center creation near the surface of synthetic diamond using an in situ nitrogen
delta-doping technique during plasma-enhanced chemical vapor deposition.
Despite their proximity to the surface, doped NV centers with depths (d)
ranging from 5 - 100 nm display long spin coherence times, T2 > 100 \mus at d =
5 nm and T2 > 600 \mus at d \geq 50 nm. The consistently long spin coherence
observed in such shallow NV centers enables applications such as atomic-scale
external spin sensing and hybrid quantum architectures.Comment: 14 pages, 4 figures, 11 pages of additional supplementary materia
Revealing quantum Hall states in epitaxial topological half-Heusler semimetal
Prediction of topological surface states (TSS) in half-Heusler compounds
raises exciting possibilities to realize exotic electronic states and novel
devices by exploiting their multifunctional nature. However, an important
prerequisite is identification of macroscopic physical observables of the TSS,
which has been difficult in these semi-metallic systems due to prohibitively
large number of bulk carriers. Here, we introduce compensation alloying in
epitaxial thin films as an effective route to tune the chemical potential and
simultaneously reduce the bulk carrier concentration by more than two orders of
magnitude compared to the parent compound. Linear magnetoresistance is shown to
appear as a precursor phase that transmutes into a TSS induced quantum Hall
phase on further reduction of the coupling between the surface states and the
bulk carriers. Our approach paves the way to reveal and manipulate exotic
properties of topological phases in Heusler compounds.Comment: 8 pages, 4 figures. Supplementary Infromation contains 7 sections and
17 figure
Molecular Ligands Control Superlattice Structure and Crystallite Orientation in Colloidal Quantum Dot Solids
Colloidal quantum
dot solids represent a new materials platform
that has garnered interest for a variety of electronic, optoelectronic,
and photovoltaic applications. In such solids, individual quantum
dots must be coupled with each other to facilitate charge transport
through the solid. Past improvements on charge transport of colloidal
quantum dot solids have been achieved primarily through the control
of the interparticle spacing. However, the role of morphological ordering
of the crystalline facets of individual quantum dots on the charge
transport of the quantum dot solid is unknown. Here, we show for the
first time that small passivating ligand molecules around the quantum
dots can control the arrangement of different facets of quantum dots
within the quantum dot solid. The insights from this study provide
important directions for future enhancement in orientation of quantum
dots in colloidal quantum dot solids
THz spectroscopy of self-assembled ErSb Nanowires
We report on self-assembled ErSb nanowires in a GaSb matrix that show a strong polarization-sensitive THz response. The nanowires behave like a polarizer. Their orientation and shape can be engineered by the growth conditions