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arXiv · 1707.08469

Effect of electron-hole asymmetry on optical conductivity in 8-Pmmn borophene

Sonu Verma·Alestin Mawrie·Tarun Kanti Ghosh
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Abstract

We present a detail theoretical study of the Drude weight and optical conductivity of 8-$Pmmn$ borophene having tilted anisotropic Dirac cones. We provide exact analytical expressions of $xx$ and $yy$ components of the Drude weight as well as maximum optical conductivity. We also obtain exact analytical expressions of the minimum energy ($ε_1$) required to trigger the optical transitions and energy ($ε_2$) needed to attain maximum optical conductivity. We find that the Drude weight and optical conductivity are highly anisotropic as a consequence of the anisotropic Dirac cone. The optical conductivities have a nonmonotonic behavior with photon energy in the regime between $ε_1$ and $ε_2$, as a result of the tilted parameter $v_t$. The tilted parameter can be extracted by knowing $ε_1$ and $ε_2$ from optical measurements. The maximum values of the components of the optical conductivity do not depend on the carrier density and the tilted parameter. The product of the maximum values of the anisotropic conductivities has the universal value $(e^2/4\hbar)^2$. The tilted anisotropic Dirac cones in 8-$Pmmn$ borophene can be realized by the optical conductivity measurement.

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Sonu Verma, Alestin Mawrie, Tarun Kanti Ghosh. 2017-10-02. Effect of electron-hole asymmetry on optical conductivity in 8-Pmmn borophene. https://doi.org/10.1103/physrevb.96.155418

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