scholarly journals Singlet fission for quantum information and quantum computing: the parallel JDE model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kori E. Smyser ◽  
Joel D. Eaves

Abstract Singlet fission is a photoconversion process that generates a doubly excited, maximally spin entangled pair state. This state has applications to quantum information and computing that are only beginning to be realized. In this article, we construct and analyze a spin-exciton hamiltonian to describe the dynamics of the two-triplet state. We find the selection rules that connect the doubly excited, spin-singlet state to the manifold of quintet states and comment on the mechanism and conditions for the transition into formally independent triplets. For adjacent dimers that are oriented and immobilized in an inert host, singlet fission can be strongly state-selective. We make predictions for electron paramagnetic resonance experiments and analyze experimental data from recent literature. Our results give conditions for which magnetic resonance pulses can drive transitions between optically polarized magnetic sublevels of the two-exciton states, making it possible to realize quantum gates at room temperature in these systems.

1996 ◽  
Vol 452 ◽  
Author(s):  
N. H. Nickel ◽  
E. A. Schiff

AbstractThe temperature dependence of the silicon dangling-bond resonance in polycrystalline (poly-Si) and amorphous silicon (a-Si:H) was measured. At room temperature, electron paramagnetic resonance (EPR) measurements reveal an isotropie g-value of 2.0055 and a line width of 6.5 and 6.1 G for Si dangling-bonds in a-Si:H and poly-Si, respectively. In both materials spin density and g-value are independent of temperature. While in a-Si:H the width of the resonance did not change with temperature, poly-Si exhibits a remarkable T dependence of ΔHpp. In unpassivated poly-Si a pronounced decrease of ΔHpp is observed for temperatures above 300 K. At 384 K ΔHpp reaches a minimum of 5.1 G, then increases to 6.1 G at 460 K, and eventually decreases to 4.6 G at 530 K. In hydrogenated poly-Si ΔHpp decreases monotonically above 425 K. The decrease of ΔHpp is attributed to electron hopping causing motional narrowing. An average hopping distance of 15 and 17.5 Å was estimated for unhydrogenated and H passivated poly-Si, respectively.


Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3449
Author(s):  
Ireneusz Stefaniuk ◽  
Werner Obermayr ◽  
Volodymyr D. Popovych ◽  
Bogumił Cieniek ◽  
Iwona Rogalska

In this paper, we show a simple method of producing ferromagnetic materials with a Curie temperature above room temperature. The electron paramagnetic resonance (EPR) spectra of Cd1−xCrxTe (0.002 < x < 0.08) were measured with a dependence on temperature (82 K < T < 381 K). Obtained EPR lines were fitted to a Lorentz-shaped curve. The temperature dependencies of the parameters of the EPR lines, such as the peak-to-peak linewidth (Hpp), the intensity (A), as well as the resonance field (Hr), were studied. Ferromagnetism was noticed in samples at high temperatures (near room temperature). For a sample with a nominal concentration of chrome of x = 0.05, a very strong intrinsic magnetic field is observed. The value of the effective gyromagnetic factor for this sample is ge = 30 at T = 240 K. An increase of chrome concentration above x = 0.05 reduces the ferromagnetic properties considerably. Analysis of the temperature dependencies of the integral intensity of EPR spectra was carried out using the Curie–Weiss law and the paramagnetic Curie temperature was obtained.


1969 ◽  
Author(s):  
D.A. Bozanic ◽  
D.C. Buck ◽  
F.H. Harris ◽  
R.E. Huber ◽  
D. Mergerian ◽  
...  

1991 ◽  
Vol 46 (7) ◽  
pp. 579-582 ◽  
Author(s):  
A. B. Vassilikou-Dova ◽  
K. Eftaxias

Abstract In clear, blue, transparent bipyramidal crystals of the rare mineral benitoite, BaTiSi3O9, para­ magnetic defects have been investigated by electron paramagnetic resonance at room temperature and 9.43 GHz. They are attributed to Sn3+ and Fe3+ . A pair of satellites recorded for a wide angular rage around B0 || c (~40°) and a relative intensity of ~ 13% to the central signal is most likely due to hyperfine interaction with 117Sn and 119Sn isotopes. Attempts to bleach the colour of the crystal were unsuccessful.


Biochemistry ◽  
1993 ◽  
Vol 32 (18) ◽  
pp. 4842-4847 ◽  
Author(s):  
Ina Sieckmann ◽  
Klaus Brettel ◽  
Christian Bock ◽  
Arthur van der Est ◽  
Dietmar Stehlik

2002 ◽  
Vol 744 ◽  
Author(s):  
N. Y. Garces ◽  
Lijun Wang ◽  
M. M. Chirila ◽  
L. E. Halliburton ◽  
N. C. Giles

ABSTRACTZinc oxide (ZnO) crystals grown by the seeded chemical vapor transport method have been studied using photoluminescence (PL), thermoluminescence (TL), and electron paramagnetic resonance (EPR) techniques. Lithium acceptors were diffused into the crystals during anneals in LiF powder at temperatures in the 750 to 850°C range. After a lithium diffusion, EPR was used to monitor neutral lithium acceptors and neutral shallow donors, as well as Ni3+, Fe3+, and Cu2+ impurities unintentionally present. Excitonic and deep-level PL emissions were also monitored before and after these diffusions. Two broad overlapping TL emission bands were observed at 117 and 145 K when a Li-diffused crystal was illuminated at 77 K with 325-nm light and then rapidly warmed to room temperature. The two TL bands have the same spectral dependence (the peak in wavelength is 540 nm when the intensity of the light reaches a maximum). These “glow” peaks occur when electrons are thermally released from Ni2+ and Fe2+ ions and recombine with holes at neutral lithium acceptors.


2005 ◽  
Vol 60 (7) ◽  
pp. 549-553 ◽  
Author(s):  
Şemsettin Osmanoğlua ◽  
Murat Aydın ◽  
M. Halim Başkana

The electron paramagnetic resonance spectra of γ -irradiated L-glutamine hydrochloride and N-carbamoyl- L-glutamic acid single crystals have been investigated at room temperature. Radiation damage centres are attributed to ĊH, ṄH2 and CH2Ċ(NH2)COOH radicals.


1995 ◽  
Vol 99 (12) ◽  
pp. 4324-4329 ◽  
Author(s):  
Karl Laukenmann ◽  
Stefan Weber ◽  
Gerd Kothe ◽  
Claudia Oesterle ◽  
Alexander Angerhofer ◽  
...  

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