Browsing by Author "Ullrich, Carsten A."
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Asymmetry of abovethreshold ionization of metal clusters in twocolor laser fields: A timedependent densityfunctional study
Nguyen, H. S.; Bandrauk, A. D.; Ullrich, Carsten A. (American Physical Society, 200406)Above threshold ionization (ATI) spectra of small metal clusters (e.g., Na4 and Na4+) are calculated numerically using a spherical jellium model and timedependent density functional theory for twocolor (1064 and 532 ... 
Coherent control of intersubband optical bistability in quantum wells
Wijewardane, Harshani Ovamini, 1971; Ullrich, Carsten A. (American Institute of Physics, 200404)We present a study of the nonlinear intersubband (ISB) response of conduction electrons in a GaAs/Al0.3Ga0.7As quantum well to strong terahertz (THz) radiation, using a densitymatrix approach combined with timedependent ... 
Collective chargedensity excitations of noncircular quantum dots in a magnetic field
Ullrich, Carsten A.; Vignale, Giovanni, 1957 (American Physical Society, 200001)Recent photoabsorption measurements have revealed a rich fine structure in the collective chargedensity excitation spectrum of fewelectron quantum dots in the presence of magnetic fields. We have performed systematic ... 
Collective intersubband transitions in quantum wells: A comparative densityfunctional study
Ullrich, Carsten A.; Vignale, Giovanni, 1957 (American Physical Society, 199812)We use linearized timedependent (current) densityfunctional theory to study collective transitions between the two lowest subbands in GaAs/AlxGa1xAs quantum wells. We focus on two particular systems, for both of which ... 
Degenerate ground states and nonunique potentials: Breakdown and restoration of density functionals
Capelle, K.; Ullrich, Carsten A.; Vignale, Giovanni, 1957 (American Physical Society, 200707)The HohenbergKohn (HK) theorem is one of the most fundamental theorems of quantum mechanics, and constitutes the basis for the very successful densityfunctional approach to inhomogeneous interacting manyparticle systems. ... 
Dissipation through spin Coulomb drag in electronic spin dynamics
D'Amico, Irene; Ullrich, Carsten A. (arXiv, 200509)Spin Coulomb drag (SCD) constitutes an intrinsic source of dissipation for spin currents in metals and semiconductors. We discuss the power loss due to SCD in potential spintronics devices and analyze in detail the associated ... 
Dissipation through spin Coulomb drag in electronic spin transport and optical excitations
D'Amico, Irene; Ullrich, Carsten A. (American Physical Society, 200609)Spin Coulomb drag (SCD) constitutes an intrinsic source of dissipation for spin currents in metals and semiconductors. We discuss the power loss due to SCD in potential spintronics devices and analyze in detail the associated ... 
Enhanced carrier scattering rates in dilute magnetic semiconductors with correlated impurities
Kyrychenko, F. V.; Ullrich, Carsten A. (American Physical Society, 200701)In IIIV dilute magnetic semiconductors such as Ga1−xMnxAs, the impurity positions tend to be correlated, which can drastically affect the electronic transport properties of these materials. Within the memory function ... 
Erratum: Timedependent currentdensityfunctional theory for the linear response of weakly disordered systems Phys. Rev. B 65, 245102 (2002)
Ullrich, Carsten A.; Vignale, Giovanni, 1957 (American Physical Society, 200412)See Also: Original Article: C. A. Ullrich and G. Vignale, Timedependent currentdensityfunctional theory for the linear response of weakly disordered systems, Phys. Rev. B 65, 245102 (2002). 
Excitation energies from timedependent densityfunctional theory beyond the adiabatic approximation
Ullrich, Carsten A.; Burke, Kieron (American Institute of Physics, 200404)Timedependent densityfunctional theory in the adiabatic approximation has been very successful for calculating excitation energies in molecular systems. This paper studies nonadiabatic effects for excitation energies, ... 
Intersubband spinorbit coupling and spin splitting in symmetric quantum wells
Kyrychenko, F. V.; Ullrich, Carsten A.; D'Amico, Irene (arXiv, 200710)In semiconductors with inversion asymmetry, spinorbit coupling gives rise to the wellknown Dresselhaus and Rashba effects. If one considers quantum wells with two or more conduction subbands, an additional, intersubbandinduced ... 
Linewidths of collective excitations of the inhomogeneous electron gas: Application to twodimensional quantum strips
Ullrich, Carsten A.; Vignale, Giovanni, 1957 (American Physical Society, 199809)t is well known that highfrequency collective excitations in electronic systems are not Landau damped, i.e., they cannot decay effectively into single particlehole pairs. The leading damping mechanism in this regime is ... 
Memory function formalism approach to electrical conductivity and optical response of dilute magnetic semiconductors
Kyrychenko, F. V.; Ullrich, Carsten A. (arXiv, 200704)A combination of the memory function formalism and timedependent densityfunctional theory is applied to transport in dilute magnetic semiconductors. The approach considers spin and charge disorder and electronelectron ... 
Nonadiabatic electron dynamics in timedependent densityfunctional theory
Ullrich, Carsten A.; Tokatly, I. V. (American Physical Society, 200606)Timedependent densityfunctional theory (TDDFT) treats dynamical exchange and correlation (xc) via a singleparticle potential, Vxc(r,t), defined as a nonlocal functional of the density n(r′,t′). The popular adiabatic ... 
Nonlinear Intersubband Photoabsorption in Asymmetric Single Quantum Wells
Wijewardane, Harshani Ovamini, 1971; Ullrich, Carsten A. (American Institute of Physics, 200506)A densitymatrix approach combined with timedependent densityfunctional theory is used to calculate the intersubband photoabsorption in a strongly driven, DCbiased GaAs/AlGaAs single quantum well. For certain frequencies ... 
Nonuniqueness in spindensityfunctional theory on lattices
Ullrich, Carsten A. (American Physical Society, 200508)In electronic manyparticle systems, the mapping between densities and spin magnetizations, {n(r),m(r)}, and potentials and magnetic fields, {v(r),B(r)}, is known to be nonunique, which has fundamental and practical ... 
Physical signatures of discontinuities of the timedependent exchangecorrelation potential
Viera, Daniel; Capelle, K.; Ullrich, Carsten A. (Royal Society of Chemistry, 200904)The exact exchangecorrelation (XC) potential in timedependent densityfunctional theory (TDDFT) is known to develop steps and discontinuities upon change of the particle number in spatially confined regions or isolated ... 
RealTime Electron Dynamics with ExactExchange TimeDependent DensityFunctional Theory
Wijewardane, Harshani Ovamini, 1971; Ullrich, Carsten A. (American Physical Society, 200802)The exact exchange potential in time dependent densityfunctional theory is defined as an orbital functional through the timedependent optimized effective potential (TDOEP) method. We numerically solve the TDOEP integral ... 
Response properties of IIIV dilute magnetic semiconductors: interplay of disorder, dynamical electronelectron interactions and bandstructure effects
Kyrychenko, F. V.; Ullrich, Carsten A. (arXiv, 201101)A theory of the electronic response in spin and charge disordered media is developed with the particular aim to describe IIIV dilute magnetic semiconductors like GaMnAs. The theory combines a detailed k.p description of ... 
Spin gaps and spinflip energies in densityfunctional theory
Capelle, K.; Vignale, Giovanni, 1957; Ullrich, Carsten A. (American Physical Society, 201003)Energy gaps are crucial aspects of the electronic structure of finite and extended systems. Whereas much is known about how to define and calculate charge gaps in densityfunctional theory (DFT), and about the relation ...