Quantum Mechanics for Material Science

   by Adil Aftab

   Mon,18, 2021

Quantum mechanics, also known as quantum theory, is a principle that even its own creators struggled to fully understand and which turned out to be the only perspective capable of explaining the behavior of matter in the microscopic world. Electronics is a subset of physics and is the science that analyzes the motion of electrons. As semiconductor-based electronics become smaller, more quantum mechanical phenomena will need to be considered in their design. This is why understanding quantum effects are so important in this context.

Many characteristics of metals, such as electrical and thermal conductivity, optical properties, and magnetic activity, are quantum mechanical in nature. Statistical thermodynamics is used to calculate the equilibrium distributions of point defects in metals, with a little help from quantum mechanics here and there.

Quantum physics is used to explain how electrons move through a computer chip, how photons of light convert to electrical current in a solar panel or amplify themselves in a laser in an optical fiber, and even how the sun continues to burn. Engineers and scientists have developed a whole series of macro models such as BJTs and FETs to define the behavior of electrons to travel in certain states.

Quantum mechanics tells us that an electron can occupy only certain energy levels. When looking at a large group of electrons, such as those found in semiconductors, these levels are “bands,” or ranges of permissible energy values. When the semiconductor is connected to a voltage that is within the energy band, it conducts electricity. When connected to a voltage outside the allowable energy band, the device does not conduct electricity; it acts as an insulator. This is how the transistors, composed of semiconductor material, turn on or off, and the computer reads it as 1 or 0 bits.

Semiconductor materials, which are the basis of present-day electronics, are considered to be among the most promising systems for future nanoelectronics. More specifically, semiconductor materials have a key role in the creation of what physicists call quantum networks, or devices capable of transporting and processing information encoded in quantum states.