Shaffique Adam

Strange metals are an intriguing class of conductors that exhibit unconventional electronic properties.  These poorly understood materials are usually identified by a linear-in-temperature dependence of resistivity and a linear-in-field dependence of magnetotransport. We focus on the electronic transport properties of twisted bilayer graphene, a material that some claim exhibits strange metal behaviour.  Our previous work has demonstrated that at small twist angles, the resistivity displays a linear-in-temperature behaviour well below the Bloch–Gruneisen temperature [1]. Building on this result, we show that magnetotransport also exhibits a similar linear behaviour over a wide range of magnetic fields. We determine the window in parameter space for the apparent strange metal behaviour defined by the co-existence of linear-in-temperature resistivity and linear-in-field magnetotransport. Interestingly, our imitation strange metal becomes less robust for dirtier samples, which is in contrast to the behaviour of real strange metals according to recent theories. These findings highlight the potential for ordinary metals to imitate strange metal behaviour and emphasise the need for careful interpretation of experimental results.

[1] G. Sharma, I. Yudhistira, N. Chakraborty, D. Y. H. Ho, M. M. A. Ezzi, M. S. Fuhrer, G. Vignale, and S. Adam, Nature Communications 12, 5737 (2021)