Multivalley envelope function equations and effective potentials for phosphorus impurity in silicon

AbstractElectron and ion beams are indispensable tools in numerous fields of science and technology, ranging from radiation therapy to microscopy and lithography. Advanced beam control facilitates new functionalities. Here, we report the guiding and splitting of charged particle beams using ponderomotive forces created by the motion of charged particles through electrostatic optics printed on planar substrates. Shape and strength of the potential can be locally tailored by the lithographically produced electrodes’ layout and the applied voltages, enabling the control of charged particle beams within precisely engineered effective potentials. We demonstrate guiding of electrons and ions for a large range of energies (from 20 to 5000 eV) and masses (from 5 · 10−4 to 131 atomic mass units) as well as electron beam splitting for energies up to the keV regime as a proof-of-concept for more complex beam manipulation.

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Spontaneous symmetry breaking and linear effective potentials

Physical Review D ◽

10.1103/physrevd.86.025028 ◽

2012 ◽

Vol 86 (2) ◽

Cited By ~ 3

Author(s):

J. Alexandre

Keyword(s):

Symmetry Breaking ◽

Spontaneous Symmetry Breaking ◽

Effective Potentials

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OPTICAL ABSORPTION SPECTRA OF ARSENIC AND PHOSPHORUS IN SILICON

Canadian Journal of Physics ◽

10.1139/p62-156 ◽

1962 ◽

Vol 40 (10) ◽

pp. 1480-1489 ◽

Cited By ~ 19

Author(s):

J. W. Bichard ◽

J. C. Giles

Keyword(s):

Optical Absorption ◽

Absorption Spectra ◽

Excited States ◽

Ground State ◽

Absorption Lines ◽

Full Width ◽

Optical Absorption Spectra ◽

Phosphorus Impurity ◽

Line Widths ◽

Phosphorus In Silicon

The optical absorption spectra of arsenic and phosphorus donor impurities in silicon have been studied under conditions of improved resolution. Absorption lines due to transitions from the impurity ground state to the excited states 2p0, 2p±, 3p0, 3p±, 4p0, 4 p±, and 5p0, and 5p± have been observed at 4.2° K. The relative intensities of some of these absorption lines are compared with existing experimental and theoretical estimates. The contribution of instrumental broadening to the observed line widths is assessed and natural line widths are estimated. The estimates indicate values for the natural line widths which are much less than those previously reported. For phosphorus impurity, the natural line widths are estimated to be less than 0.08 × 10−3 electron volts full width at half-maximum. The possibility of concentration broadening is discussed in connection with the arsenic data.

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Minimal Optimized Effective Potentials for Density Functional Theory Studies on Excited-State Proton Dissociation

Micromachines ◽

10.3390/mi12060679 ◽

2021 ◽

Vol 12 (6) ◽

pp. 679

Author(s):

Pouya Partovi-Azar ◽

Daniel Sebastiani

Keyword(s):

Density Functional Theory ◽

Excited State ◽

Proton Transfer ◽

Density Functional ◽

Photochemical Reactions ◽

Transfer Energy ◽

Functional Theory ◽

Effective Potentials ◽

Proton Dissociation ◽

Dissociation Curves

Recently, a new method [P. Partovi-Azar and D. Sebastiani, J. Chem. Phys. 152, 064101 (2020)] was proposed to increase the efficiency of proton transfer energy calculations in density functional theory by using the T1 state with additional optimized effective potentials instead of calculations at S1. In this work, we focus on proton transfer from six prototypical photoacids to neighboring water molecules and show that the reference proton dissociation curves obtained at S1 states using time-dependent density functional theory can be reproduced with a reasonable accuracy by performing T1 calculations at density functional theory level with only one additional effective potential for the acidic hydrogens. We also find that the extra effective potentials for the acidic hydrogens neither change the nature of the T1 state nor the structural properties of solvent molecules upon transfer from the acids. The presented method is not only beneficial for theoretical studies on excited state proton transfer, but we believe that it would also be useful for studying other excited state photochemical reactions.

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Time-Rescaling of Dirac Dynamics: Shortcuts to Adiabaticity in Ion Traps and Weyl Semimetals

Entropy ◽

10.3390/e23010081 ◽

2021 ◽

Vol 23 (1) ◽

pp. 81

Author(s):

Agniva Roychowdhury ◽

Sebastian Deffner

Keyword(s):

Time Dependence ◽

Unitary Transformation ◽

Ion Traps ◽

Time Frame ◽

Effective Potentials ◽

Shortcuts To Adiabaticity ◽

Weyl Semimetals ◽

Adiabatic Dynamics

Only very recently, rescaling time has been recognized as a way to achieve adiabatic dynamics in fast processes. The advantage of time-rescaling over other shortcuts to adiabaticity is that it does not depend on the eigenspectrum and eigenstates of the Hamiltonian. However, time-rescaling requires that the original dynamics are adiabatic, and in the rescaled time frame, the Hamiltonian exhibits non-trivial time-dependence. In this work, we show how time-rescaling can be applied to Dirac dynamics, and we show that all time-dependence can be absorbed into the effective potentials through a judiciously chosen unitary transformation. This is demonstrated for two experimentally relevant scenarios, namely for ion traps and adiabatic creation of Weyl points.

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