6,794 research outputs found
Flux dependent 1.5 MeV self-ion beam induced sputtering from Gold nanostructured thin films
We discuss four important aspects of 1.5 MeV Au2+ ion-induced flux dependent
sputtering from gold nanostrcutures (of an average size 7.6 nm and height 6.9
nm) that are deposited on silicon substrates: (a) Au sputtering yield at the
ion flux of 6.3x10^12 ions cm-2 s-1 is found to be 312 atoms/ion which is about
five times the sputtering yield reported earlier under identical irradiation
conditions at a lower beam flux of 10^9 ions cm-2 s-1, (b) the sputtered yield
increases with increasing flux at lower fluence and reduces at higher fluence
(1.0x10^15 ions cm-2) for nanostructured thin films while the sputtering yield
increases with increasing flux and fluence for thick films (27.5 nm Au
deposited on Si) (c) Size distribution of sputtered particles has been found to
vary with the incident beam flux showing a bimodal distribution at higher flux
and (d) the decay exponent obtained from the size distributions of sputtered
particles showed an inverse power law dependence ranging from 1.5 to 2.5 as a
function of incident beam flux. The exponent values have been compared with
existing theoretical models to understand the underlying mechanism. The role of
wafer temperature associated with the beam flux has been invoked for a
qualitative understanding of the sputtering results in both the nanostructured
thin films and thick films.Comment: 25 pages, 5 figures, 1 table To be Appeared in J. Phys. D: Appl. Phy
Trap-assisted space charge limited transport in short channel MoS2 transistor
We present temperature dependent measurements of short channel MoS
field effect devices at high source-drain bias. We find that although the
characteristics are Ohmic at low bias, the conduction becomes space charge
limited at high and existence of an exponential distribution of trap
states was observed. The temperature independent critical drain-source voltage
() was also determined. The density of trap states was quantitatively
calculated from . The possible origin of exponential trap distribution in
these devices is also discussed.Comment: 5 pages, 3 figure
Classical light vs. nonclassical light: Characterizations and interesting applications
We briefly review the ideas that have shaped modern optics and have led to
various applications of light ranging from spectroscopy to astrophysics, and
street lights to quantum communication. The review is primarily focused on the
modern applications of classical light and nonclassical light. Specific
attention has been given to the applications of squeezed, antibunched, and
entangled states of radiation field. Applications of Fock states (especially
single photon states) in the field of quantum communication are also discussed.Comment: 32 pages, 3 figures, a review on applications of ligh
Theory of superconductivity with non-Hermitian and parity-time reversal symmetric cooper pairing symmetry
Recently developed parity (P) and time-reversal (T) symmetric non-Hermitian
systems govern a rich variety of new and characteristically distinct physical
properties, which may or may not have a direct analog in their Hermitian
counterparts. We study here a non-Hermitian, PT-symmetric superconducting
Hamiltonian that possesses real quasiparticle spectrum in the PT-region of the
Brillouin zone. Within a single-band mean-field theory, we find that real
quasiparticle energies are possible when the superconducting order parameter
itself is either Hermitian or anti-Hermitian. Within the corresponding
Bardeen-Cooper-Schrieffer (BCS) theory, we find that several properties are
characteristically distinct and novel in the non-Hermitian pairing case than
its Hermitian counterpart. One of our significant findings is that while a
Hermitian superconductor gives a second order phase transition, the
non-Hermitian one produces a robust first order phase transition. The
corresponding thermodynamic properties, and the Meissner effect are also
modified accordingly. Finally, we discuss how such a PT-symmetric pairings can
emerge from an anti-symmetric potential, such as the Dzyloshinskii-Moria
interaction, but with an external external bath, or complex potential, among
others.Comment: 15 pages including appendices (2 columns), (v2): Hermitian pairing
solution of the DM interaction is added; and conditions for obtaining
non-Hermitian pairings are further delineate
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