Comment from Christian Joachim,
CEMES/CNRS, 29 Rue J. Marvig, BP 94347, 31055
Toulouse Cedex, France
on The Mysteries at the Nanoscale

Here is a future which can be called nanoscience
because the subject of the experiment is no more a
material but a single individual molecule.

Toulouse, le 11 Octobre 2005

Dear Editor,

Thanks for communicating the reaction of Pr. G. J. Salamo to my paper ¹. I am very sorry to have disturbed the social club of nanoscience and nanotechnology. Of course material science is fascinating for the new devices and for their new properties invented or to be discovered. But do we have to invent a new name for those research activities? As mentioned ¹, they result from inventions of new instruments and techniques which appear at the beginning to the middle of the twentieth century: X-rays diffractometer, electron microscopy, epitaxy, self assembly of molecular monolayer, e-beam lithography, just to name a few.

Let us imagine that G. Bining and H. Rohrer had not invented the scanning tunnelling microscope (STM) in 1982 and D. Eigler not discovered single atom manipulation in 1991. Material science will continue to go on and the control of materials at the atomic scale will continue using all the characterisation tools mentioned above. Even atomic and molecular monolayer characterisations would be practiced using for example razing X-Rays facilities and the razing e-beam instrumentation would have been pushed further. This would be nurturing “technologies for future electronic, opto-electronic and electromechanical devices” as quoted by Pr. Salamo together with certainly very interesting science resulting. In the 80’s many solid state physicists where calling this science “mesocopic physics”, a very good terminology according to the L. de Broglie classification ¹.

As observers or participants, we have the chance to be at a breaking point in the history of science and technology: the invention of a new instrument, the STM and the growing of a new technique atomic and molecular manipulation, one at a time. Thanks for Pr. Salamo appreciation, “the manipulation of atoms and molecule is beautifully accomplished”. Atomic and molecular manipulation may be “a miracle” as written by Pr. Salamo. But it is a commercial miracle. One can buy on the market LT UHV STM which guaranty atom by atom manipulation. Two companies are selling those products. There is no mystery here, only technology that scientists and engineers are pushing again and again to the limits for the benefit of both. Like any such breaking point in history, we cannot appreciate on the spot what will come after: only a craft for laboratory (as implicitly expressed in his paper by Pr. Salamo) or a full technological revolution as predicted by others. But we do appreciate that playing with a single molecule, exploring intramolecular behaviours inside a single and always the same molecule open new scientific avenues. Here is a future which can be called nanoscience because the subject of the experiment is no more a material but a single individual molecule.

To finish with, a word about self-assembly. There is no mystery about self-assembly, this is physics and chemistry. In many books, the confusion is that self-assembly is loosely related to life. Then, come such strange sentence like ”new mysterious behaviours” in the Pr. Salamo comments. Optical, electrical mechanical properties coming from nano materials are not unusual intrinsically, there are unusual compared to the properties of previous materials. This doesn’t means that they are mysterious nor that they are resulting from a new science. Another way of thinking is open by atom and molecular manipulation: designing, fabricating (synthesizing) unimolecular machine integrating all the functionality inside the same molecule (large or small). There is no need to assemble (or self assemble) a material to fabricate a device or a machine. What are the laws of Nature which are forcing us for doing so? Staying at the bottom, avoiding the bottom-up approach is a difficult problem of communication: how to exchange information, energy order with a single molecule. This is a real difficult technical problem for scientists and engineers. Here is Nanoscience and certainly not in a social self assembly between material science and mesoscopic physics.

C. Joachim

¹ C. Joachim, Nature Material, 4, 107 (2005)