The recent advancements in physics have led to a significant breakthrough. Scientists at the University of L’Aquila in Italy have gained a full microscopic understanding of the superconductivity of Mercury – a development more than a century in the making.
Understanding Superconductivity
Superconductivity is a state in which a material conducts electricity without any resistance. This is typically observed when certain materials are cooled significantly, below a specific critical temperature, causing them to exhibit this unique characteristic.
The Discovery of Superconductivity in Mercury
The phenomenon of superconductivity was first discovered in Mercury by Heike Kamerlingh Onnes in 1911. Contributing to this discovery was Onnes’s innovative method to cool materials down to absolute zero – the lowest possible temperature. He observed that solid mercury, when cooled to an extremely low threshold temperature, displayed no resistance to the flow of electric current. This discovery marked a significant turning point in the field of physics.
Methodologies Explaining Superconductivity in Mercury
There have been various methodologies used to explain the superconductivity of Mercury:
The BCS Theory
The Bardeen-Cooper-Schrieffer (BCS) theory contributes to our understanding of superconductivity. Here, vibrational energy released by a grid of atoms prompts electrons to pair up, forming Cooper pairs. These pairs can move unimpeded, facing no resistance to their flow, below a certain threshold temperature. This could explain why Mercury has a particularly low threshold temperature (around –270°C).
Spin-Orbit Coupling
Spin-Orbit Coupling (SOC) explains the effect of an electron’s energy being influenced by its spin and momentum. SOC provides a clearer view of phonons’ energies and is another reason why Mercury has such a low threshold temperature (approximately –270º C).
The Role of Coulomb Repulsion
Coulomb repulsion also plays a key role in the superconductivity process. It refers to the repulsive interaction between two ‘like’ charges, in this case, two electrons in each pair. The superconducting state is determined by a balance between an attractive interaction between electrons, which is mediated by phonons, and the repulsive Coulomb interaction.
About Mercury
Mercury is a naturally occurring element found in air, water, and soil. It is released into the environment through natural processes such as weathering of rocks, volcanic eruptions, geothermal activities, and forest fires. Human activities also contribute to mercury releases. Notably, Mercury is the only metal that remains liquid at room temperature.
UPSC Civil Services Examination Question
The improper or indiscriminate disposal of old computers or their parts can release certain harmful elements into the environment as e-waste. In 2013, the UPSC Civil Services Examination asked candidates to identify these elements. They included: Beryllium, Cadmium, Chromium, Heptachlor, Mercury, Lead, and Plutonium. The correct answer was options 1, 2, 3, 5 and 6, indicating that Beryllium, Cadmium, Chromium, Mercury, and Lead are among the waste elements resulting from improperly discarded computer hardware.
