Question: Discovery by scientist of which institute has challenges theory of superconductivity?
(a) Tata Institute of Fundamental Research
(b) IIT Kanpur
(c) Indian Institute of science
(d) None of the above.
Ans: (a)
Related facts:
- An exciting discovery by Tata Institute of Fundamental Research (TIFR), Mumbai, recently published in Science (online 1st Dec 2016) has challenged the conventional understanding of superconductivity.
- A team, lead by Dr. S. Ramakrishnan of the Department of Condensed Matter Physics and Material Sciences at TIFR, has discovered bismuth semi-metal in bulk form becoming a superconductor when the temperature is lowered to 530 microKelvin (about -273 degree C).
- This is three orders of magnitude higher than the theoretical prediction.
- The Bardeen-Cooper-Schrieffer (BCS) theory [which explains superconductivity in most low Tc superconductors] cannot explain the superconductivity seen in bismuth
- Superconductors are materials that conduct electricity with no resistance whatsoever. To become superconductors, the element should have mobile electrons, and these electrons should come together to form pairs, known as Cooper pairs.
- Unlike other elements in the periodic table, bismuth has unusual phenomenon. While metallic superconductors have one mobile electron per atom, bismuth has only one mobile electron per 100,000 atoms.
Also, bismuth’s electronic energy (Fermi energy) is comparable to the lattice (phonon) energy. So the conventional BCS theory and its extensions which assume that Fermi energy is two to three orders of magnitude higher than phonon energy is not valid in bismuth. - BCS theory or Bardeen–Cooper–Schrieffer theory (named after John Bardeen, Leon Cooper, and John Robert Schrieffer) is the first microscopic theory of superconductivity since its discovery in 1911. The theory describes superconductivity as a microscopic effect caused by a condensation of Cooper pairs into a boson-like state. The theory is also used in nuclear physics to describe the pairing interaction between nucleons in an atomic nucleus.
- Tata Institute of Fundamental Research is a National Centre of the Government of India, under the umbrella of the Department of Atomic Energy, as well as a deemed University awarding degrees for master’s and doctoral programs. The Institute was founded in 1945 with support from the Sir Dorabji Tata Trust under the vision of Dr Homi Bhabha.
Reference:
http://www.tifr.res.in/TSN/news_detail.php?id=108
https://www.sciencenews.org/article/despite-lack-free-electrons-bismuth-superconducts?tgt=nr
http://www.thehindu.com/sci-tech/science/TIFR-discovery-challenges-theory-of-superconductivity/article16769407.ece