July 11, 2006 IEEE SCV EDS Meeting:

"Ohm's Law"

Speaker: Professor Inder P. Batra -
University of Illinois at Chicago
Subject: "Ohm's Law"
Location: National Semiconductor, Building 31 Large Auditorium,
955 Kifer Road, Sunnyvale, CA.   See the meeting location map
Time: 6:00 PM - Pizza , 6:15 PM - Lecture
Speaker Contact: Ranjeet K. Pancholy

Abstract:

In this talk, we discuss transport through nanostructures in a rudimentary manner. We review Ohm’s law in the classical domain, starting from Drude model and learn how far it succeeded in “explaining” Ohm’s law.

Conduction and quantized Hall resistance in narrow channels have been well understood by using the two-dimensional electron gas (2DEG), a model system which has been realized in semiconductor hetero junctions.

An essential property of the 2DEG is its ability to produce a constriction of width comparable to the Fermi wavelength; a property not shared by even thin metal films.

But the advent of scanning tunneling microscopy (STM) has enabled scientists to fabricate wires of “atomic” dimensions. This has led to an explosion of interest in the electronic and transport properties of nanostructures.

Or did Drude simply rewrite Ohm’s law in a more sophisticated “language”? Then with some trepidation, we talk about Ohm’s law in the semi-classical and quantum domain.

Is there an Ohm’s Law in the quantum domain? The title of a recent paper by N. D. Lang, “Anomalous Dependence of Resistance on Length in Atomic Wires” (Phys. Rev. Letters 79, 1357, 1997), already contains a partial answer to the question just posed.

Abstract (Continued):

We discuss these issues at a more superficial level and provide an alternate way of understanding (Landauer) conductance quantization through “atomic” wires.

My proposal simply is that the origin of quantum conductance lies in Heisenberg’s uncertainty principle, which is the demarcation line between Classical and Quantum domain. But whatever happened to the density of states and the E (k) relations as the basis for Ohm’s Law?

That too is an uncertainty!

I close by reviewing the ultimate miniaturization based on the uncertainty principle arguments.

Biography:

Inder P. Batra’s scientific career, which spans nearly three decades, gave him an opportunity to work at the three premier IBM Research laboratories (Almaden, Watson, and Zurich) and then as a Professor (his current position) at University of Illinois at Chicago.

He always engaged in the cutting edge fundamental and technical issues ranging from optical absorption in semiconductors, the underlying theory of scanning tunneling microscopy, to the stability and transport properties of nanostructures.

He is currently engaged in electronic, transport and structural calculations for metallic and atomic nanowires using density functional theory and other analytical methods.

For more information on   Professor Inder P. Batra

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