Navinder Singh

• Anomalous electronic transport in the strange metal regime of (un)conventional superconductors
• Theory of (un)conventional superconductivity (i.e.in Cuprates, heavy fermions, and Fe based compounds)

ELECTRONIC TRANSPORT IN STRANGE METALS:: Electronic transport in simple metals can be understood using quasiparticle concept and the Bloch-Boltzmann kinetic theory. However, in strange metals (like, normal states of Cuprates, heavy fermion, and iron based superconductors) electronic transport mechanisms remain elusive. We are interested in such cases, and the Mori-Zwanzig memory function formalism can provide partial answers. However, the problems remain open.
A very basic introduction is given in:

THEORY OF (UN)CONVENTIONAL SUPERCONDUCTIVITY (i.e. in Cuprates, heavy electron materials, and Fe based compounds) Theory of conventional superconductivity known as BCS (Bardeen-Cooper-Schrieffer) theory is successful in explaining the superconducting behaviour of some metals and simple compounds. It cannot be applied to cuprates and Fe based compounds (called high temperature superconductors) as the pairing mechanisms in these new compounds are not due to phonons and it does not have an adequate foundation as normal state of these compounds shows non-Fermi Liquid behaviour. Understanding the physics of cuprates and Fe based compounds represent a long-standing and challenging problem in condensed matter physics. These materials are very poor conductors of electricity in their normal state but become superconducting at very high temperatures in comparison to conventional superconductors. Despite over 3 decades of research on the cuprates, a comprehensive microscopic theory does not exist and there is no consensus on their underlying pairing mechanism.

• The Gor’kov–Teitel’baum Thermal Activation Model for Cuprates: A review.
  Navinder Singh. J Low Temp. Phys. (2024). DOI :10.1007/s10909-024-03188-w.



• Pseudogap in Sr2−xLaxIrO4: Gor'kov-Teitel'baum thermal activation model.
  Authors: Jalaja Pandya, Devarshi Dave, Navinder Singh. Phys Lett. A. Vol 507, 129469 (2024)..



• Tunable phase transitions in half-Heusler TbPtBi compound.
  Authors: Pratik D. Patel, Akariti Sharma, Bharathiganesh Devanarayanan, Paramita Dutta, Navinder Singh. J. Phys.: Condens. Matter, 35, 035501, (2023).



• The case of itinerant magnetism in CaMn2Al10: self-consistent renormalisation (SCR) theory study
  Authors: Bharathiganesh Devanarayanan, Akariti Sharma, Pratik D Patel1, and Navinder Singh. J. Phys.: Condens. Matter 34 465802 (2022).



• Leading theories of the cuprate superconductivity: a critique
  Authors: Navinder Singh. Physica C: Superconductivity and its applications, Vol. 580, 1353782 (2021).



• The memory function formalism: an overview
  Authors: Komal Kumari and Navinder Singh, Eur. J. Phys. Vol. 41, 053001 (2020).



• A theory of resistivity in Kondo lattice materials: the memory function approach
  Authors: Komal Kumari, Raman Sharma, Navinder Singh. Ref. J. Phys. Cond. Matt. Vol. 32. 425603 (2020).
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• Resistivity of a 2d quantum critical metal
  Authors: Komal Kumari, Raman Sharma, Navinder Singh. Ref. Phys. Lett. A. Vol. 383, 2645 (2019).
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• Quantum oscillations of the Stoner susceptibility: theory
  Authors: Ajeet Kumar, Raman Sharma, Navinder Singh Ref. Journal of Magnetism and Magnetic Materials, Vol. 487, 165302 (2019).
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• Non-equilibrium electron relaxation in Graphene
  Authors: Luxmi Rani, Pankaj Bhalla, Navinder Singh Ref. International Journal of Modern Physics B. Vol. 33, No. 17, 1950183 (2019).
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• A Novel Effect of Electron Spin Resonance on Electrical Resistivity
  Authors: Navinder Singh, Luxmi Rani. Ref. Journal of Magnetism and Magnetic Materials, Volume 474, Pages 501-504 (2019).
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• A comparative study of finite frequency scattering rate from Allen, Mitrovic-Fiorucci, Shulga-Dolgov-Maksimov, Sharapov-Carbotte and Goetze-Woelfle Memory Function formalisms
  Authors: Pankaj Bhalla, Navinder Singh. Ref. Int. J. Mod. Phys. B. Vol. 33, 1950128 (2019).
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• Dynamical electrical conductivity of graphene
  Authors: Luxmi Rani and Navinder Singh. Ref. J. Phys: Cond. Matt. Vol. 29, 255602 (2017).
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• Finite frequency Seebeck coefficient of metals: A memory function approach
  Authors: Pankaj Bhalla, Pradeep Kumar, Nabyendu Das, Navinder Singh. Ref: Journal of Physics and Chemistry of Solids, Vol. 109, 31 (2017).
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• Moment Expansion to the Memory Function for Generalized Drude Scattering rate
  AAuthors: Pankaj Bhalla, Nabyendu Das, Navinder Singh. Ref. Physics Letters A, Vol. 380, 2000 (2016).
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• Impurity induced resistivity upturns in underdoped cuprates
  Authors: Nabyendu Das, Navinder Singh. Ref. Phys. Lett. A, Vol. 380, 490 (2016).
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