Sunday, January 16, 2022

Bosonic strange metals and oscillatory behavior of magnetoresistance

Strange metals are difficult to understand in the standard paradigm. Linear dependence with respect to temperature instead of quadratic in fermionic liquids is one problem. In the TGD framework, dark particles as ordinary particles with effective Planck constant heff=nh0>h at magnetic flux tubes, explains this: see the blog posting or the article TGD and condensed matter.

In the article "Signatures of a strange metal in a bosonic system" by Yang et al published in Nature, bosonic strange metals are studied instead of fermionic ones. The system can also be superconducting and this seems to be essential.

The linear dependence on magnetoresistance in an external magnetic field B is the second interesting phenomenon.

  1. Below the onset of temperature Tc1>Tc, the low-field magneto-resistance varies with a periodic dictated by superconducting flux quantum suggesting that the density of charge carriers varies with this period.
  2. What comes to mind is the De Haas-Van Alphen effect in field B (see this).

    The magnetic susceptibility of the system varies periodically with the inverse of the magnetic flux Φ = e ∫ BdS defined by extremal orbit of electrons at the Fermi surface in field B. Φ is measured in units defined by elementary flux quantum h/2e.

  3. Could spin=0 Cooper pairs be formed from the electrons at the Fermi surface and lead to the De Haas-Van Alphen effect. They would go to the flux tubes of the external magnetic field B with a rate determined by the magnetic flux.

    The rate for this highest, when the extremal orbit at the Fermi surface corresponds to a quantized flux. Otherwise, energy is needed to kick the electrons from the Fermi surface to a larger orbit in order to satisfy the flux quantization condition.

Now one considers magnetoresistance rather than susceptibility. The linearity in magnetoresistance suggests that the resistance in the external field is mostly due to magnetoresistance.
  1. Could the analog of the De Haas-Van Alphen effect be present so that the density of Cooper pairs as current carriers at "endogenous" magnetic flux tubes has an oscillatory behavior as a function of the external magnetic field B? Could there be a competition for the Cooper pairs between the magnetic fields of flux tubes and external magnetic field B?
  2. When the flux Φ for the external B is near the multiple of the elementary flux quantum at extremal orbits at Fermi surface, the formation of spin=0 Cooper pair and transgder to the flux tubes of B would become probable by De-Haas-van Alphen effect. The number of Cooper pairs at "endogenous" flux tubes is therefore reduced and the current therefore reduced.
See the article TGD and condensed matter or the chapter with the same title.

For a summary of earlier postings see Latest progress in TGD.

Articles and other material related to TGD.

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