The Swiss Federal Laboratories for Materials Science and Technology (EMPA) and the EPFL research team have developed the world’s smallest engine. The engine, which consists of only 16 atoms, consists of moving parts like other macro-scale engines. The size of the motor is about 100,000 times smaller than the diameter of a human hair.
It has a stator and rotor like normal motors and the working principle is the same. Such molecular motors also exist in nature – in the form of myosins, for example. Myosins are motor proteins that play an important role in living organisms in the contraction of muscles and the transport of other molecules on their paper.
The molecular motor consists of a moving part and a stationary part. The stationary part of the engine consists of 6 palladium atoms and 6 gallium atoms combined in a pyramid shape. The moving part of the engine is an acetylene molecule with 4 atoms moving above its constant.
To prevent the motor from reversing, they fixed the direction of rotation using a ratchet (gear mechanism) scheme.
However, the atomic motor works with the asymmetric serrated gear wheel in contrast to what happens with a ratchet in the macroscopic world: In a ratchet, the claw moves the straight edge up and locks around the perpendicular edge, while the atomic variable less energy to move the edge of the gear wheel more than the straight edge. Movement in the blockage direction, which is this process, is preferred, and movement in the direction of travel is much less likely. Thus the movement is possible almost on one wheel.
The Swiss scientific team implemented it in a minimal variant using a stator with a basically triangular structure of six palladium and six gallium atoms. The trick here is that this structure is rotationally symmetrical but mirror-symmetrical.
As a result, the rotor consisting of only four atoms (asymmetrical acetylene molecule) can rotate, but clockwise and counterclockwise rotation must be different. “The motor has 99% directionality that sets it apart from other similar molecular motors”
Working Principle of Molecular Engine
Atom motor can be powered by both thermal and electrical energy. Thermal energy can cause revolutions in the direction of rotation of the motor – rotating, the rotor can rotate at several million revolutions per second.
When electrical energy is applied to the motor, electric current can cause turns with an electron scanning microscope. The energy of a single electron is enough to keep the rotors spinning for only one-sixth of a revolution.
The rotation speed of the motor is directly proportional to the amount of energy supplied. The higher the amount of energy to the motor, the higher the frequency the motor rotates.
According to the laws of classical physics, there is a minimum amount of energy required to activate the rotor. The researchers observed that it operated at temperatures below -256 ° C or with the energy of fewer than 30 millivolts in a fixed direction and a constant rotation frequency.
From Classical Physics to the Quantum World
Swiss scientists explained that this way the engine moves by realizing a phenomenon called quantum tunneling.
Quantum Tunneling raises other questions for the molecular engine. Quantum tunneling is thought to occur without friction. When the motor performs without this motion, the motion of the moving part will create motion. However, achieving 99 percent motion comes from saving some of the energy during quantum tunneling.
The emergence of the world’s smallest engine could reveal smaller-than-expected mechanisms in the future and more information about quantum tunneling. Oliver Gröning, the principal investigator of the engine development study, said the engine’s energy distribution processes and causes could drive quantum tunneling studies.