Planckain metal and anomalous density fluctuations in high-Tc cuprate superconductors

A mysterious Planckian strange metal phase, characterized by a perfect linear-in-temperature resistivity with a universal T-linear scattering rate 1/τ = 2 π a k_B T /h (a~1) and a logarithmic temperature dependance of the specific heat, has been observed in high-Tc cuprate superconductors near optimal doping [1]. In our recent work, we proposed a microscopic mechanism for this exotic emergent quantum many-body phase based on heavy-fermion approach to the slave-boson t-J model [2]. Via controlled perturbative renormalization group analysis, we found a quantum critical phase where the scattering rate exhibits Planckian transport [2]. Here, following Ref. [2], we compute the charge susceptibility, a measure of correlation of electron density fluctuations, in the Planckian metal phase of our model [3]. Our results offer an excellent description of anomalous (momentum-independent) density fluctuations in strange metal state observed in cuprates by M-EELS technique [4].



[1] A. Legros et al., Nat. Phys. 15, 142 (2019).

[2] Y.-Y Chang et al., arXiv:2406.14858.

[3] K. Remund et al., (un-published).

[4] M. Mitrano et al., PNAS 115 (21), 5392–5396 (2018).