Craig Lent - Academia.edu (original) (raw)

Papers by Craig Lent

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS—I: FUNDAMENTAL THEORY AND APPLICATIONS, VOL. 47, NO. 8, AUGUST 2000, 2000

Abstract—The Nano-Devices Group at the University of Notre Dame proposed a new device that encod... more Abstract—The Nano-Devices Group at the University of Notre
Dame proposed a new device that encodes information in the
geometrical charge distribution of artificial (or natural) molecules.
Functional units are composed by electrostatic coupling. In these
units, processing takes place by reshaping the electron density of
the molecules, and not by switching currents [1]. Signal processing
potential of next-neighbor-coupled cellular nonlinear networks
(CNN’s) has been recently explored with the conclusion that
local-activity of the cells is necessary to exhibit complexity [2].
It will be shown that Coulomb-coupled time-invariant artificial
molecules behave like nonlinear locally passive devices, thus
signal-power-gain or multiple equilibria cannot be achieved by
integrating them. However, the signal input–output relation of
strongly nonlinear molecules can be varied in time by adiabatic
pumping, called clock control. It will be shown that strongly
nonlinear time-varying molecules can transform the necessary
amount of clock energy into the signal flow, thereby enabling the
network of molecules to perform signal processing.

We present an experimental demonstration of a fanout gate for quantum-dot cellular automata (QCA)... more We present an experimental demonstration of a fanout gate for quantum-dot cellular automata (QCA), where a signal applied to a single input cell is amplified by that cell and sent to two output cells. Each cell is a single-electron latch composed of three metal dots, which are connected in series by tunnel junctions. Binary information is represented by an excess

ABSTRACT Landauer's principle connects the logical reversibility of computational operati... more ABSTRACT Landauer's principle connects the logical reversibility of computational operations to physical reversibility and hence to energy dissipation, with important theoretical and practical consequences. We report the first experimental test of Landauer's principle. For logically reversible operations we measure energy dissipations much less than kB Tlog 2, while irreversible operations dissipate much more than kB Tlog 2. Measurements of a logically reversible operation on a bit with energy 30 kB T yield an energy dissipation of 0.01 kB T.

The Journal of Chemical Physics, 2015

Low-temperature scanning tunneling microscopy is used to observe self-assembled structures of fer... more Low-temperature scanning tunneling microscopy is used to observe self-assembled structures of ferrocenedicarboxylic acid (Fc(COOH)2) on the Au(111) surface. The surface is prepared by pulse-deposition of Fc(COOH)2 dissolved in methanol, and the solvent is evaporated before imaging. While the rows of hydrogen-bonded dimers that are common for carboxylic acid species are observed, the majority of adsorbed Fc(COOH)2 is instead found in six-molecule clusters with a well-defined and chiral geometry. The coverage and distribution of these clusters are consistent with a random sequential adsorption model, showing that solution-phase species are determinative of adsorbate distribution for this system under these reaction conditions.

Nature, 2014

The process of molecular self-assembly on solid surfaces is essentially one of crystallization in... more The process of molecular self-assembly on solid surfaces is essentially one of crystallization in two dimensions, and the structures that result depend on the interplay between intermolecular forces and the interaction between adsorbates and the underlying substrate. Because a single hydrogen bond typically has an energy between 15 and 35 kilojoules per mole, hydrogen bonding can be a strong driver of molecular assembly; this is apparent from the dominant role of hydrogen bonding in nucleic-acid base pairing, as well as in the secondary structure of proteins. Carboxylic acid functional groups, which provide two hydrogen bonds, are particularly promising and reliable in creating and maintaining surface order, and self-assembled monolayers of benzoic acids produce structure that depends on the number and relative placement of carboxylic acid groups. Here we use scanning tunnelling microscopy to study self-assembled monolayers of ferrocenecarboxylic acid (FcCOOH), and find that, rather than producing dimeric or linear structures typical of carboxylic acids, FcCOOH forms highly unusual cyclic hydrogen-bonded pentamers, which combine with simultaneously formed FcCOOH dimers to form two-dimensional quasicrystallites that exhibit local five-fold symmetry and maintain translational and rotational order (without periodicity) for distances of more than 400 ångströms.

Journal of nanoscience and nanotechnology

Quantum-Dot Cellular Automata (QCA) is a computational scheme utilizing the position of interacti... more Quantum-Dot Cellular Automata (QCA) is a computational scheme utilizing the position of interacting single electrons within arrays of quantum dots ("cells") to encode and process binary information. Clocked QCA architectures can provide power gain, logic level restoration, and memory features. Using arrays of micron-sized metal dots, we experimentally demonstrate operation of a QCA latch-inverter and a two-stage shift register.

Physical Review A, 2001

Quantum-dot cellular automata (QCA), arrays of coupled quantum-dot devices, are proposed for quan... more Quantum-dot cellular automata (QCA), arrays of coupled quantum-dot devices, are proposed for quantum computing. The notion of coherent QCA (CQCA) is introduced in order to distinguish QCA applied to quantum computing from classical digital QCA. Information is encoded in the spatial state of the electrons in the multidot system. A line of CQCA cells can work as a quantum register.

2012 12th IEEE International Conference on Nanotechnology (IEEE-NANO), 2012

ABSTRACT Power dissipation is one of the most important factors limiting the development of integ... more ABSTRACT Power dissipation is one of the most important factors limiting the development of integrated circuits. This work will explore the limits of energy dissipation in computation and show that there is no "Landauer Limit" at k(B)T ln2 as long as information is preserved. Experimental data is presented that demonstrates a dissipation of 0.04 k(B)T, well below kBT ln2. Simulation results for adiabatically clocked reversible circuits are presented showing dramatic reductions of power dissipation.

Proceedings of the 2001 1st IEEE Conference on Nanotechnology. IEEE-NANO 2001 (Cat. No.01EX516), 2001

58th DRC. Device Research Conference. Conference Digest (Cat. No.00TH8526), 2000

Digest. International Electron Devices Meeting,, 2002

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1998

2011 IEEE International Symposium of Circuits and Systems (ISCAS), 2011