Transition-metal dichalcogenides showing type-II Dirac fermions are emerging as innovative materials for nanoelectronics. However, their excitation spectrum is mostly unexplored yet. By means of high-resolution electron energy loss spectroscopy and density functional theory, here, we identify the collective excitations of type-II Dirac fermions (3D Dirac plasmons) in PtTe_2 single crystals. The observed plasmon energy in the long-wavelength limit is ∼0.5  eV, which makes PtTe_2 suitable for near-infrared optoelectronic applications. We also demonstrate that interband transitions between the two Dirac bands in PtTe_2 give rise to additional excitations at ∼1 and ∼1.4  eV. Our results are crucial to bringing to fruition type-II Dirac semimetals in optoelectronics.

3D Dirac Plasmons in the Type-II Dirac Semimetal PtTe_2

Politano, Antonio;Chiarello, Gennaro
;
2018

Abstract

Transition-metal dichalcogenides showing type-II Dirac fermions are emerging as innovative materials for nanoelectronics. However, their excitation spectrum is mostly unexplored yet. By means of high-resolution electron energy loss spectroscopy and density functional theory, here, we identify the collective excitations of type-II Dirac fermions (3D Dirac plasmons) in PtTe_2 single crystals. The observed plasmon energy in the long-wavelength limit is ∼0.5  eV, which makes PtTe_2 suitable for near-infrared optoelectronic applications. We also demonstrate that interband transitions between the two Dirac bands in PtTe_2 give rise to additional excitations at ∼1 and ∼1.4  eV. Our results are crucial to bringing to fruition type-II Dirac semimetals in optoelectronics.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/288742
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