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

Kimberly Remund^1,2*, Khoe Van Nguyen¹, Chung-Hou Chung^1,2

¹Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan
²Physics Division, National Center for Theoretical Sciences, Taipei, Taiwan

* Presenter:Kimberly Remund, email:remund@nycu.edu.tw

A mysterious Planckian strange metal phase, characterized by a perfect linear-in-temperature resistivity with a universal T-linear scattering rate ħ/τ = a kBT (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 a heavy-fermion approach of 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).

Keywords: Strange metals, Planckian metallic phase, anomalous density fluctuations