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arXiv · 1802.03585

Theory of Friedel oscillations in monolayer graphene and group-VI dichalcogenides in a magnetic field

Tomasz M. Rusin·Wlodek Zawadzki
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Abstract

Friedel oscillations (FO) of electron density caused by a delta-like neutral impurity in two-dimensional (2D) systems in a magnetic field are calculated. Three 2D cases are considered: free electron gas, monolayer graphene and group-VI dichalcogenides. An exact form of the renormalized Green's function is used in the calculations, as obtained by a summation of the infinite Dyson series and regularization procedure. Final results are valid for large ranges of potential strengths $V_0$, electron densities $n_e$, magnetic fields $B$ and distances from the impurity $r$. Realistic models for the impurities are used. The first FO of induced density in WS$_2$ are described by the relation $Δn(\vec{r}) \propto \sin(2πr/T_{FO})/r^2$, where $T_{FO} \propto 1/\sqrt{E_F}$. For weak impurity potentials, the amplitudes of FO are proportional to $V_0$. For attractive potentials and high fields the total electron density remains positive for all $r$. On the other hand, for low fields, repulsive potentials and small $r$, the total electron density may become negative, so that many-body effects should be taken into account.

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Tomasz M. Rusin, Wlodek Zawadzki. 2018-05-08. Theory of Friedel oscillations in monolayer graphene and group-VI dichalcogenides in a magnetic field. https://doi.org/10.1103/physrevb.97.205410

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