Christian Joachim, pilot of the race for “picomachines”, invisible to the naked eye

Christian Joachim, CNRS research director, in his office at the Center for the Development of Materials and Structural Studies (Cemes), in Toulouse, July 6, 2006. HUBERT RAGUET/CEMES/CNRS PHOTOTHEQUE What game is he playing ? In the basement of his laboratory at the Center for the Development of Materials and Structural Studies (Cemes), in Toulouse, Christian Joachim, assisted by Umamahesh Thupakula, a postdoctoral student, is perplexed. Like a mikado lover, thanks to commands sent from his keyboard to an imposing machine, he pushes a stick invisible to the naked eye. Without success. He shoots it. It does not work either. He tries with a double push. Same. He then scribbles his next strategy on a sheet of paper. Will she be the right one? Will he be able to achieve the feat of raising this 50-nanometer-long rod on a step some twenty nanometers high – one nanometer is one billionth of a meter, less than the diameter of a cut hair? in 100,000? Achieving this would please this pioneer of a discipline first called biotics in the 1970s, then molecular electronics a few years later. The idea is to succeed in concentrating in a single molecule the functions of the components of current electronics, resulting from the nanometric shaping of materials such as silicon. Switch, wire, amplifier, transistor, adder… all on a molecule, ten to a hundred times smaller in size than current materials. If we do not really understand his funny game, it is also difficult to put the researcher, who has just turned 65, in a box. Chemist ? Physicist? Or even a mathematician? A bit of all three for this CNRS silver medalist in 2001. Five-legged sheep Since he manipulates molecules, he should be classified as a chemist. “But he has a physicist’s vision of it,” corrects Erik Dujardin, CNRS researcher at the Carnot Interdisciplinary Laboratory in Burgundy, who worked for a long time at Cemes with him. He is not interested in their usual property of crystallization or phase change, but he imagines how their state of energy will make it possible to carry out a function. He even invented names for these molecules, outside the official nomenclatures, which makes the eyes of chemists widen. “I like to draw five-legged sheep on the blackboard to stimulate my colleagues who will try to make them,” says Christian Joachim, who remembers having imagined, while still a student, a first molecular thread on the blackboard in his room. “He sure likes to draw! But chemists sometimes brought it back down to earth,” recalls Jean-Pierre Launay, former director of Cemes. You have 70.57% of this article left to read. The following is for subscribers only.