Thermal plasmons controlled by different thermal-convolution paths in tunable extrinsic Dirac structures

Abstract

Analytic expressions for chemical potentials without any approximations are derived for all types of extrinsic (doped) gapped Dirac-cone materials including gapped graphene, silicene, germanene and single-layer transition metal dichalcogenides. In setting up our derivations, a reliable piecewiselinear model has been established for calculating the density-of-states in molybdenum disulfide, showing good agreement with previously obtained numerical results. For spin-and valley-resolved band structures, a decrease of chemical potential with increasing temperature is found as a result of enhanced thermal populations of an upper subband. Due to the broken symmetry with respect to electron and hole states in MoS2, the chemical potential is shown to cross a zero-energy point at sufficiently high temperatures. It is important to mention that the chemical potential at a fixed temperature can still be tuned by varying doping density and band structure of a system with an external electric or strain field. Since a thermal-convolution path (or a chemical-potential-dependent response function for the thermal convolution of fermions) starting from zero temperature must be selected in advance before obtaining finite-temperature properties of any collective quantities, e.g., polarizability, plasmon modes and damping, a control of their thermal dependence within a certain temperature range is expected for field-tunable extrinsic gapped Dirac-cone materials.

Entropy per particle spikes in the transition metal dichalcogenides

“…The peculiarities of DOS in TMDCs beyond the Dirac approximations are discussed in [28,29]. The quadratic part of the Hamiltonian (7) results in the curving of the linear in energy pieces seen in Fig.…”

Tailoring plasmon excitations in α − T3 armchair nanoribbons

“…For that reason, there is no unified analytic expression for all three terms in Eq. (20). The two remaining terms of Eq.…”

“…[12][13][14] Similarly, the plasmons were extensively studies in graphene 15,16 and other bulk Dirac materials. After more than a decade of uninterrupted efforts, [17][18][19][20][21][22][23][24] many-body theory on low-dimensional materials has finally been developed and becomes a huge resource for in-depth exploration of plasmon dynamical properties. This success is mainly attributed to accurately calculating the dynamical polarization function, 25 which is also related to the effect of static screening on transport properties of electrons.…”

Signatures of Lifshitz transition in the optical conductivity of tilted Dirac materials

“…Among them, 2D tilted Dirac materials host tilted dispersions along a certain direction of wave vector and have been attracting increasing interests theoretically and experientially [3,[9][10][11][12][13][16][17][18][19][20]. They exhibit many significant qualitative differences in physical behaviors compared to their untilted counterparts, including plasmons [21][22][23][24][25], optical conductivities [21,[26][27][28][29][30][31][32], Weiss oscillation [33], Klein tunneling [34,35], Kondo effects [36], RKKY interactions [37,38], planar Hall effect [39], and thermoelectric effects [40].…”