Memristor

A friend of us (Francisco J. Garcia) has pointed out a recent paper in Nature Letters (Vol 453| 1 May 2008| doi:10.1038/nature06932). I post here the abstract, because it is very interesting, though not very related to compact modeling:

Authors: Dmitri B. Strukov, Gregory S. Snider, Duncan R. Stewart & R. Stanley Williams

ABSTRACT: Anyone who ever took an electronics laboratory class will be familiar with the fundamental passive circuit elements: the resistor, the capacitor and the inductor. However, in 1971 Leon Chua reasoned from symmetry arguments that there should be a fourth fundamental element, which he called a memristor (short for memory resistor). Although he showed that such an element has many interesting and valuable circuit properties, until now no one has presented either a useful physical model or an example of a memristor.

Here we show, using a simple analytical example, that memristance arises naturally in nanoscale systems in which solid-state electronic and ionic transport are coupled under an external bias voltage. These results serve as the foundation for understanding a wide range of hysteretic current–voltage behaviour observed in many nanoscale electronic devices2–19 that involve the motion of charged atomic or molecular species, in particular certain titanium dioxide cross-point switches20–22.

There is a remarks to be done, following Francisco, since you can find a patent of a very similar device:
Genrikh et al
US Patent Application Publication No. US 2007/0200158 A1, Aug. 30, 2007
ELECTRODE STRUCTURE HAVING AT LEAST TWO OXIDE LAYERS AND NON-VOLATILE MEMORY DEVICE HAVING THE SAME
Assignee: Samsung Electronics, Co., Ltd.
Filed: Jan. 19, 2007