TSU scientists are developing molecular switches for electronics
25.08.2016

Physicists at Tomsk State University and their German colleagues are conducting calculations of new properties of organic molecules that arise during their interaction with a metal surface. These properties can have applications in molecular electronics.

Compared with traditional semiconductor electronics, molecular electronics based on the use of organic molecules have many advantages. One of them is minimal energy consumption. Another advantage is the large variety of organic molecules with different properties, which leads to more opportunity for creating technological devices.

The Department for Physics of Semiconductor (Faculty of Physics) has been studying the behavior of organic molecules on metal surfaces.

- There are two ways that molecules interact with a metal surface: the formation of a chemical bond between the molecule and the metal, and the attraction by the Van der Waals forces - says Sergey Filimonov, Associate Professor at the Department for Physics of Semiconductor (Faculty of Physics). - It is believed that the connection of van der Waals forces is much weaker than the chemical bond. However, there are systems in which the contribution of the interaction of these species is comparable. Such systems can have unusual properties that can be used to create new types of electronic devices.

The scientists chose triazine – a derivative of benzene, a molecule with the rigid hexagonal structure - as the organic material. It was believed that such molecules do not undergo significant deformation when interacting with the metal, and their properties remain unchanged. However, during the research, it was discovered that this is not the case. On a metal surface under the influence of van der Waals forces, a molecule is bent and acquires new properties.

If the connection of the molecule with a metal is changed by means of external exposure, it is possible to get a so-called molecular switch and used it as a memory element: in one state the molecule acts as a zero and in the other acts as a one. Because the molecule size is very small, it allows recording much more information per square centimeter.

Tomsk scientists are calculating the molecular properties by a method developed at Fritz Haber Institute of the Max Planck Society (Germany), which was visited recently by Sergey Filimonov:

- Our colleagues from Germany have been developing methods for calculating the electronic structure of materials. One of the methods allows you to precisely take into account the van der Waals forces. We use it to calculate the strength of the interaction in the metal–molecule system that we study.