Metal-Insulator Transition (MIT)

Why in news?

• Scientists have found the reason behind how certain materials can change from being good conductors of electricity (metallic) to insulators (materials in which electric current does not flow freely). 

About Metal-Insulator Transition

• In materials that act as insulators, electrons are tightly bound to their atoms, making it difficult for them to move freely. As a result, these materials do not conduct electricity effectively.
• In metals, electrons are free to move throughout the material, allowing for good electrical conductivity. This is due to the presence of a “sea” of delocalized electrons that can carry an electric current.
• The metal-insulator transition occurs when the electrical properties of a material change from insulating behavior to conducting behavior or vice versa. This transition can be induced by altering external factors like temperature, pressure, or the concentration of impurities in the material.
• One of the well-known examples of a metal-insulator transition is in vanadium dioxide (VO2) at a certain critical temperature. Below this temperature, VO2 is an insulator, but above it, it becomes a metal.

New finding

• Scientists have found the reason behind how certain materials can change from being good conductors of electricity (metallic) to insulators.
• They used one of the metal-insulator transition (MIT) materials called chromium nitride (CrN) to demonstrate this.
• They have found that the magnetic stress caused by the arrangement of atoms in a material can be the reason for this transition of materials from metallic to insulators.

PRACTICE QUESTION

Consider the following statements regarding metal-insulator transition:

1. They are primarily observed in non-metals.
2. When electrons are tightly bound to the atoms, conductivity is low.

Which of the statements given above is/are correct?

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Answer