520 research outputs found
Affect Infusion and Detection through Faces in Computer-mediated Knowledge-sharing Decisions
Faces are important in both human communication and computer-mediated communication. In this study, I analyze the influence of emotional expressions in faces on knowledge-sharing decisions in a computer-mediated environment. I suggest that faces can be used for affect infusion and affect detection, which increases the effectiveness of knowledge-management systems. Using the affect infusion model, I discuss why emotions can be expected to influence knowledge-sharing decisions. Using the two-step primitive emotional contagion framework, I found that emotional facial expression attached to a knowledge-sharing request influenced knowledge-sharing decisions. This influence was mediated by the decision maker’s emotional valence in the facial expression tracked by Face Reader technology and held for females but not males. I discuss implications for designers of emotionally intelligent information systems and research
EFFECTS OF IRRELEVANT ALTERNATIVES IN RELATIVE PERFORMANCE EVALUATION
In this study we examine the effect of the presence of irrelevant performance information on the rank order decisions made by supervisors in relative performance evaluation (RPE). Specifically, we investigate the effect of two types of irrelevant performance information patterns in what has been termed an asymmetric dominated decoy and a viable decoy. We also examine whether relative performance information (RPI) size (evaluating 3 versus 9 subordinates at a time) can moderate the adverse influence of irrelevant information. The empirical results from our experiment support that the asymmetrically dominated decoy information pattern (where an additional subordinate is included in the RPE whose performance is similar to and is dominated by one of the original subordinates – referred to as the target subordinate) can increase the rank ordering of the target subordinate. Contrary to our expectation, we do not find that the viable decoy information pattern (where an additional subordinate is included in the RPE whose performance is partially dominating the target subordinate) has a significant influence on the rank ordering decisions of subordinates. Our results also provide support for an interaction between the decoy information and RPI size for the asymmetric dominated decoy such that the rank order effect is only present when the RPI size is small (evaluating 3 subordinates in our case). Our study informs designers of accounting information systems in several ways
Classical ratchet effects in heterostructures with a lateral periodic potential
We study terahertz radiation induced ratchet currents in low dimensional
semiconductor structures with a superimposed one-dimensional lateral periodic
potential. The periodic potential is produced by etching a grating into the
sample surface or depositing metal stripes periodically on the sample top.
Microscopically, the photocurrent generation is based on the combined action of
the lateral periodic potential, verified by transport measurements, and the
in-plane modulated pumping caused by the lateral superlattice. We show that a
substantial part of the total current is caused by the polarization-independent
Seebeck ratchet effect. In addition, polarization-dependent photocurrents
occur, which we interpret in terms of their underlying microscopical
mechanisms. As a result, the class of ratchet systems needs to be extended by
linear and circular ratchets, sensitive to linear and circular polarizations of
the driving electro-magnetic force.Comment: 11 pages, 9 figures, 2 column
Ginzburg-Landau Expansion and the Slope of the Upper Critical Field in Disordered Superconductors with Anisotropic Pairing
It is demonstrated that the slope of the upper critical field
in superconductors with -wave pairing drops rather
fast with concentration of normal impurities, while in superconductors with
anisotropic -wave pairing grows, and in the limit of
strong disorder is described by the known dependences of the theory of
``dirty'' superconductors. This allows to use the measurements of in
disordered superconductors to discriminate between these different types of
pairing in high-temperature and heavy-fermion superconductors.Comment: 7 pages, 5 figures, RevTeX 3.0, 4 Postscript figures attached;
Submitted to JETP Letter
Phenomenological BCS theory of the high- cuprates
A BCS model characterized by a phenomenological pair potential with on-site
(), nearest (), and next nearest () neighbour coupling
constants, and an empirical quasiparticle dispersion taken from angle-resolved
photoemission spectra is considered. The model can consistently explain the
experimental data concerning the pair state of the hole doped cuprates. Three
ingredients are required to make the interpretation possible: the existence of
flat bands, a very small effective on-site repulsion, and a slightly dominating
effective nnn attraction of the order of 60-80meV with a ratio .Comment: 13 pages, uuencoded Postscrip
Non-magnetic impurity scattering in a superconductor near a van Hove point: Zn versus Ni in the cuprates
We consider the effect of non-magnetic impurities in a
superconductor with \ef close to a van Hove singularity. It is shown that the
non-trivial density of states (DOS) allows for resonant scattering already at
intermediate potential strengths eV. The residual DOS at
\ef, and the \tc suppression rate are found to strongly depend on the carrier
concentration. Quantitative agreement with experiments on Zn and Ni doped
cuprates is obtained by adjusting a single parameter, .Comment: 4 pages uuencoded compressed Postscript (Minor changes
Terahertz radiation driven chiral edge currents in graphene
We observe photocurrents induced in single layer graphene samples by
illumination of the graphene edges with circularly polarized terahertz
radiation at normal incidence. The photocurrent flows along the sample edges
and forms a vortex. Its winding direction reverses by switching the light
helicity from left- to right-handed. We demonstrate that the photocurrent stems
from the sample edges, which reduce the spatial symmetry and result in an
asymmetric scattering of carriers driven by the radiation electric field. The
developed theory is in a good agreement with the experiment. We show that the
edge photocurrents can be applied for determination of the conductivity type
and the momentum scattering time of the charge carriers in the graphene edge
vicinity.Comment: 4 pages, 4 figure, additional Supplemental Material (3 pages, 1
figure
Effect of non-magnetic impurities on the gap of a superconductor as seen by angle-resolved photoemission
An analysis of angle-resolved photoemission (ARPES) experiments in the
superconducting state of the high \tc copper-oxides is presented. It is based
on a phenomenological weak-coupling BCS model which incorporates the
experimental normal state dispersion extracted from ARPES, and non-magnetic
impurity scattering in the presence of a order parameter (OP). It
is shown, that already in the pure case, the broadening by finite momentum
resolution of the analyzer leads to a finite region of apparent `gaplessness'
around the true node of the OP. Non-magnetic impurities further amplify this
effect by introducing additional spectral weight around zero frequency. At
sufficiently large impurity concentrations , this results
in an extended region of `gaplessness' up to ( the
angle on the Fermi surface) around the true node for a large range of moderate
to strong impurity potential strengths. Different ways to identify the presence
of impurity scattering in the ARPES spectra are proposed.Comment: 8 pages uuencoded gzipped Postscrip
Conductivity of CuO-Chains: Disorder versus Electron-Phonon Coupling
The optical conductivity of the CuO-chains, a subsystem of the 1-2-3
materials, is dominated by a broad peak in the mid-infrared (eV), and a slowly falling high-frequency tail. The 1D --model is
proposed as the relevant low-energy Hamiltonian describing the intrinsic
electronic structure of the CuO-chains. However, due to charge-spin
decoupling, this model alone cannot reproduce the observed \sw. We consider
two additional scattering mechanisms: (i) Disregarding the not so crucial spin
degrees of freedom, the inclusion of strong potential disorder yields excellent
agreement with experiment, but suffers from the unreasonable value of the
disorder strength necessary for the fit. (ii) Moderately strong polaronic
electron-phonon coupling to the mode involving Cu(1)-O(4) stretching, can be
modeled within a 1D Holstein Hamiltonian of spinless fermions. Using a
variational approximation for the phonon Hilbert space, we diagonalize the
Hamiltonian exactly on finite lattices. As a result of the experimental hole
density , the chains can exhibit strong charge-density-wave (CDW)
correlations, driven by phonon-mediated polaron-polaron interactions. In the
vicinity of half filling, charge motion is identified as arising from moving
domain walls, \ie defects in the CDW. Incorporating the effect of vacancy
disorder by choosing open boundary conditions, good agreement with the
experimental spectra is found. In particular, a high-frequency tail arises as a
consequence of the polaron-polaron interactions.Comment: 42 pages, ETH-TH/93-31 (Postscript
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