# Groupe de Physique Statistique

## Equipe 106, Institut Jean Lamour

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### Articles dans des revues à comité de lecture

 Non-Lifshitz-Kosevich field- and temperature-dependent amplitude of quantum oscillations in the quasi-two dimensional metal $theta$-(ET)$_4$ ZnBr$_4$(C$_6$H$_4$Cl$_2$ ) Audouard A., Fortin J.-Y., Vignolles D., Lyubovskii R. B., Drigo L.,Shilov G. V., Duc F., Zhilyaeva E. I., Lyubovskaya R. N., Canadell E. J. Phys.: Condens. Matter 27 (2015) 315601 DOI : 10.1088/0953-8984/27/31/315601 ArXiv : cond-mat/1506.0696 [PDF] According to band structure calculations, the Fermi surface of the quasi-two dimensional metal $\theta$-(ET)$_4$ZnBr$_4$(C$_6$H$_4$Cl$_2$) ill ustrates the linear chain of coupled orbits model. Accordingly, de Haas-van Alphen oscillations spectra recorded in pulsed magnetic field of u p to 55 T evidence many Fourier components, the frequency of which are linear combinations of the frequencies relevant to the closed $\alpha$ and the magnetic breakdown $\beta$ orbits. The field and temperature dependence of their amplitude are quantitatively accounted for by analy tic calculations including, beyond the Lifshitz-Kosevich formula, second order terms in damping factors due to the oscillation of the chemical potential as the magnetic field varies. Whereas these second order terms are negligible for the orbits $\alpha$, $\beta$ and $2\beta-\alpha$ , they are solely responsible for the 'forbidden orbit' $\beta-\alpha$ and its harmonic and have a significant influence on Fourier components such as $2\alpha$ and $\beta+\alpha$, yielding strongly non-Lifshitz-Kosevich behaviour in the latter case.