60,041 research outputs found
Effects of Parasitics and Interface Traps On Ballistic Nanowire FET In The Ultimate Quantum Capacitance Limit
In this paper, we focus on the performance of a nanowire Field Effect
Transistor (FET) in the Ultimate Quantum Capacitance Limit (UQCL) (where only
one subband is occupied) in the presence of interface traps (),
parasitic capacitance () and source/drain series resistance ()
using a ballistic transport model and compare the performance with its
Classical Capacitance Limit (CCL) counterpart. We discuss four different
aspects relevant to the present scenario, namely, (i) gate voltage dependent
capacitance, (ii) saturation of the drain current, (iii) the subthreshold slope
and (iv) the scaling performance. To gain physical insights into these effects,
we also develop a set of semi-analytical equations. The key observations are:
(1) A strongly energy-quantized nanowire shows non-monotonic multiple peak C-V
characteristics due to discrete contributions from individual subbands; (2) The
ballistic drain current saturates better in the UQCL compared to CCL, both in
presence and absence of and ; (3) The subthreshold slope does
not suffer any relative degradation in the UQCL compared to CCL, even with
and ; (4) UQCL scaling outperforms CCL in the ideal
condition; (5) UQCL scaling is more immune to , but presence of
and significantly degrades scaling advantages in the UQCL.Comment: Accepted at IEEE Transactions on Electron Device
Dynamics of entanglement and transport in 1D systems with quenched randomness
Quenched randomness can have a dramatic effect on the dynamics of isolated 1D
quantum many-body systems, even for systems that thermalize. This is because
transport, entanglement, and operator spreading can be hindered by `Griffiths'
rare regions which locally resemble the many-body-localized phase and thus act
as weak links. We propose coarse-grained models for entanglement growth and for
the spreading of quantum operators in the presence of such weak links. We also
examine entanglement growth across a single weak link numerically. We show that
these weak links have a stronger effect on entanglement growth than previously
assumed: entanglement growth is sub-ballistic whenever such weak links have a
power-law probability distribution at low couplings, i.e. throughout the entire
thermal Griffiths phase. We argue that the probability distribution of the
entanglement entropy across a cut can be understood from a simple picture in
terms of a classical surface growth model. Surprisingly, the four length scales
associated with (i) production of entanglement, (ii) spreading of conserved
quantities, (iii) spreading of operators, and (iv) the width of the `front' of
a spreading operator, are characterized by dynamical exponents that in general
are all distinct. Our numerical analysis of entanglement growth between weakly
coupled systems may be of independent interest.Comment: 17 pages, 16 figure
The Status of Parton Saturation and the CGC
This is a personal summary of the meeting "Saturation, the Color Glass
Condensate and Glasma: What Have we Learned from RHIC?" that took place at BNL
in May 2010. The purpose of the meeting was to discuss the status of high
density QCD and parton saturation, and to review the progress that RHIC has
allowed in the field.Comment: Summary talk of the workshop "Saturation, the Color Glass Condensate
and Glasma: What Have we Learned from RHIC?", BNL, May 2010. To be published
in Nucl. Phys.
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