Phonon-drag magnetoquantum oscillations in graphene

Abstract

A theory of low-temperature phonon-drag magnetothermopower S g xx is presented in graphene in a quantizing magnetic field. S g xx is found to exhibit quantum oscillations as a function of magnetic field B and electron concentration ne. Amplitude of the oscillations is found to increase (decrease) with increasing B (ne). The behavior of S

Phonon-drag thermopower and thermoelectric performance of MoS2 monolayer in quantizing magnetic field

“…The −S g xx is found to display the oscillatory feature caused by the oscillating DoS with the magnetic field as evinced from equation ( 16) (see figure 1), where the peak positions have been pushed to the higher field region (in comparison to those of DoS) due to the effect of phonon scatterings. This result is similar to the −S g xx behavior observed in conventional 2DEG [33,36] and MLG [37], as well as the energy loss rate behavior observed in MoS 2 monolayer [68]. One interesting fact is that the contributions to the −S g xx from τ s = 1 (K↑ and/or K ′ ↓) and τ s = −1 (K↓ and/or K ′ ↑) states are clearly separated due to the lifting of the valley and spin degeneracies in MoS 2 monolayer [9].…”

“…S g xx = ∑ λ,ν S g,λ,ν xx . We see that in the unscreened coupling case (ξ = 0), the obtained result for the S g xx has the same form as that in MLG [37].…”

“…Kubakaddi et al [31] and Fromhold et al [33] applied this approach to investigate phonon-drag thermopower in the presence of the magnetic field, called the PDMTP, in 2DEG and oscillatory behavior was predicted as a function of the magnetic field. Recently, Kubakaddi et al [37] have extended this theory to the case of 2D Dirac fermions in graphene. According to these works, in the linear response regime, the phonon heat current density is shown to be U = ME, where M is the thermoelectric tensor and E is the electric field.…”

“…According to these works, in the linear response regime, the phonon heat current density is shown to be U = ME, where M is the thermoelectric tensor and E is the electric field. The components of M are related to components S g xx and S g yx of thermopower tensor S by [33,37]…”

“…However, it will be interesting to investigate the thermoelectric transport in a quantizing magnetic field. Many studies were done to investigate the phonon-drag magnetothermopower (PDMTP), S g xx , in two-dimensional electron gas (2DEG) [30][31][32][33][34][35][36] and monolayer graphene (MLG) [37]. Their results showed that the magnetothermopower displayed an oscillatory behavior as a function of the magnetic field.…”