Matrix material structure dependence of the embedded electron spin decoherence

Abstract

In this article, we present the novel application of the nuclear spin bath model and the cluster correlation expansion method on studying the matrix material structure via embedded electron spin decoherence. Profiles of embedded electron spin decoherence under the Carr-Purcell-Meiboom-Gill dynamical decoupling pulse series in a model system for organic solids (malonic acid) are calculated for different structures. Resulting decay profiles exhibit a strong correlation to the variations of an adjacent proton environment among them. In addition, the decoherence behavior of embedded spin in proton spin bath(s) of organic solids is found to be significantly different from bath models with other nuclei through the violation of the even-odd pulse parity, which characterizes the influence of large dipolar coupling between protons at the quantum level. Theoretical predictions of decoherence profiles in polycrystalline, the relative distribution of Hahn echo signal decay time scales among single crystal orientations, and the reduction in Hahn echo signal decay time scale by disorder are positively verified by experiments.

The Electron Spin Phase Memory Decay of Stable Radical Embedded in Glassy Solvent Matrices: Nuclear Spin Bath Model

“…On the other hand, theoretical and experimental studies on the strongly interacting proton spin baths show that decay time scales tend to increase linearly with respect to increasing number of πpulses. Stretched exponents under CPMG sequences have been found to have decreased pulse parity in proton spin baths 14,27,28 . Recent experiments in glassy o-terphenyl matrix report that the long time decay stretched exponents under Uhrig sequences can increase with respect to the increasing number of π-pulses in general 14 .…”

“…The decoherence effect is induced by the interaction between nuclear spins. This leads to the following bath Hamiltonian to start with 27,28…”

“…Among other applications, development of nuclear spin bath model predicts that the decoherence time scales of embedded electron spin can be extended over the Hahn echo value by Carr-Purcell-Meilboom-Gill (CPMG) 29,30 and Uhrig 31 dynamical decoupling (DD) pulse sequences with fixed number of pulses and varying pulse separation times 14,22,[26][27][28]32,33 . Besides extending T m , these pulse sequences also induce nontrivial changes to the shapes of the deocherence profiles.…”

Dynamical decoupling in water–glycerol glasses: a comparison of nitroxides, trityl radicals and gadolinium complexes

“…In fact, the (shortest) intramolecular 1 H-1 H distance in the respective solvent molecule may rather be the decisive structural parameter. § You et al 50 performed cluster correlation expansion (CCE) calculations to demonstrate that distinct orientations of all closest proton pairs in single crystal malonic acid determine T m and x of CPMG traces with n = 1-6. Experiments confirmed these decoherence predictions as a function of single crystal orientations and suggested that the same proton pair control persists in polycrystalline malonic acid.…”

The Electron Spin Phase Memory Decay of Stable Radical Embedded in Glassy Solvent Matrices: Nuclear Spin Bath Model

“…Solving the seeming impossible quantum many-body dynamics of large number of (> 10 3 ) nuclear spins is accomplished by the dedicated cluster correlation expansion (CCE) method 20,21 . Thanking to the non-perturbative nature of CCE, the nuclear spin bath model has been found to be an efficient predictor of decoherence profiles of electron spin embedded in different nuclear spin baths and used to extract vital information of the nuclear spin environments from these profiles [22][23][24][25][26][27][28] .…”