Heisenberg spin exchange effects of nitroxide radicals on Overhauser dynamic nuclear polarization in the low field limit at 1.5mT

AbstractA strong limitation of nuclear magnetic resonance is its low inherent sensitivity that can be overcome by using an appropriate hyperpolarization technique. Presently, dynamic nuclear polarization and spin-exchange optical pumping are the only hyperpolarization techniques that are used in applied medicine. However, both are relatively complex in use and expensive. Here we present a modification of the signal amplification by reversible exchange (SABRE) hyperpolarization method – SABRE on stabilized Ir-complexes. A stabilized Ir-complex (here we used bipyridine for stabilization) can be hyperpolarized in a wide range of magnetic fields from a few μT upto 10 T with

Download Full-text

Motional Dynamics of Halogen‐Bonded Complexes Probed by Low‐Field NMR Relaxometry and Overhauser Dynamic Nuclear Polarization

Chemistry - An Asian Journal ◽

10.1002/asia.201900754 ◽

2019 ◽

Cited By ~ 1

Author(s):

Abhishek Banerjee ◽

Arnab Dey ◽

N. Chandrakumar

Keyword(s):

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Low Field ◽

Nmr Relaxometry ◽

Motional Dynamics ◽

Low Field Nmr ◽

Bonded Complexes

Download Full-text

Valley interference and spin exchange at the atomic scale in silicon

Nature Communications ◽

10.1038/s41467-020-19835-1 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

B. Voisin ◽

J. Bocquel ◽

A. Tankasala ◽

M. Usman ◽

J. Salfi ◽

...

Keyword(s):

Spin Exchange ◽

Atomic Scale ◽

Scanning Tunneling ◽

Coulomb Interactions ◽

Tunneling Microscopy ◽

Quantum Process ◽

Strongly Coupled ◽

Heisenberg Spin ◽

Heisenberg Spin Exchange ◽

Complex Phenomena

AbstractTunneling is a fundamental quantum process with no classical equivalent, which can compete with Coulomb interactions to give rise to complex phenomena. Phosphorus dopants in silicon can be placed with atomic precision to address the different regimes arising from this competition. However, they exploit wavefunctions relying on crystal band symmetries, which tunneling interactions are inherently sensitive to. Here we directly image lattice-aperiodic valley interference between coupled atoms in silicon using scanning tunneling microscopy. Our atomistic analysis unveils the role of envelope anisotropy, valley interference and dopant placement on the Heisenberg spin exchange interaction. We find that the exchange can become immune to valley interference by engineering in-plane dopant placement along specific crystallographic directions. A vacuum-like behaviour is recovered, where the exchange is maximised to the overlap between the donor orbitals, and pair-to-pair variations limited to a factor of less than 10 considering the accuracy in dopant positioning. This robustness remains over a large range of distances, from the strongly Coulomb interacting regime relevant for high-fidelity quantum computation to strongly coupled donor arrays of interest for quantum simulation in silicon.

Download Full-text

Effect of electron spin dynamics on solid-state dynamic nuclear polarization performance

Physical Chemistry Chemical Physics ◽

10.1039/c4cp02013h ◽

2014 ◽

Vol 16 (35) ◽

pp. 18694-18706 ◽

Cited By ~ 40

Author(s):

Ting Ann Siaw ◽

Matthias Fehr ◽

Alicia Lund ◽

Allegra Latimer ◽

Shamon A. Walker ◽

...

Keyword(s):

Solid State ◽

Electron Spin ◽

Dynamic Nuclear Polarization ◽

Nuclear Polarization ◽

Spin Dynamics ◽

Nitroxide Radicals ◽

Flip Flop ◽

State Dynamic ◽

Spin Flip ◽

Electron Spin Dynamics

Optimum integral EPR saturation, determined by electron T1e and electron spin flip-flop rate, maximizes solid-state DNP performance using nitroxide radicals.

Download Full-text