Quantum thermoelectrics based on two-dimensional semi-Dirac materials

Mawrie, Alestin; Muralidharan, Bhaskaran

doi:10.1103/physrevb.100.081403

Cited by 27 publications

(20 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[41]. The theoretical model used in this paper can be extended to other two-dimensional (2D) Dirac materials [44,45] as well. We obtain the AGF in the diffusive regime using the conductivity model developed by Peres et al [46].…”

Section: Introductionmentioning

confidence: 99%

Graphene as a nanoelectromechanical reference piezoresistor

Sinha

Sharma

Priyadarshi

et al. 2020

Phys. Rev. Research

Self Cite

View full text Add to dashboard Cite

Motivated by the recent prediction of anisotropy in piezoresistance of ballistic graphene along longitudinal and transverse directions, we investigate the angular gauge factor of graphene in the ballistic and diffusive regimes using highly efficient quantum transport models. It is shown that the angular gauge factor in both ballistic and diffusive graphene between 0 • to 90 • bears a sinusoidal relation with a periodicity of π due to the reduction of sixfold symmetry into a twofold symmetry as a result of applied strain. The angular gauge factor is zero at critical angles 20 • and 56 • in ballistic and diffusive regimes, respectively. Based on these findings, we propose a graphene-based ballistic nanosensor which can be used as a reference piezoresistor in a Wheatstone bridge readout technique. The reference sensors proposed here are unsusceptible to inherent residual strain present in strain sensors and unwanted strain generated by the vapors in explosives detection. The theoretical models developed in this paper can be applied to explore similar applications in other two-dimensional Dirac materials. The proposals made here potentially pave the way for implementation of nanoelectromechanical strain sensors based on the principle of ballistic transport, which will eventually replace conventional microelectromechanical piezoresistance sensors with a decrease in feature size. The presence of strain-insensitive "critical angle" in graphene may be useful in flexible wearable electronics also.

show abstract

Section: Introductionmentioning

confidence: 99%

Graphene as a nanoelectromechanical reference piezoresistor

Sinha

Sharma

Priyadarshi

et al. 2020

Phys. Rev. Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…Appendix A: Derivation of the BdG Hamiltonian Physically, the semi-Dirac dispersion can be realized in a graphene-like systems with breaking the hexagonal symmetry [7,17,20]. Thus we take an artificial honeycomb lattice model with anisotropic nearest-neighbor (NN) hopping as a prototype.…”

Section: Ns Junction Extending Along the X -Axismentioning

confidence: 99%

“…Unlike most Dirac materials that possess liner dispersions in all momentum-space directions [3][4][5], in SDMs the low-energy excitations disperse quadratically in one direction but linearly along the orthogonal direction [6][7][8][9][10]. The unique band structures of SDMs are responsible for a series of novel phenomena [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], including the consequences of anisotropic aspect in the superconducting order parameter correlations [25][26][27]. Recent theoretical efforts have demonstrated that the superconductivity in SDMs can be induced by arbitrarily weak attractions in the present of random chemical potential [25].…”

Section: Introductionmentioning

confidence: 99%

Anisotropic Andreev reflection in semi-Dirac materials

Li,

Hu,

Ouyang

2021

Preprint

View full text Add to dashboard Cite

In the framework of Bogoliubov-de Gennes equation, we theoretically study the Andreev reflection in normal-superconducting junctions based on semi-Dirac materials. Owing to the intrinsic anisotropy of semi-Dirac materials, the configuration of Andreev reflection and differential conductance are strongly orientation-dependent. For the transport along the linear dispersion direction, the differential conductance exhibits a clear crossover from retro Andreev reflection to specular Andreev reflection with an increasing bias-voltage, and the differential conductance oscillates without a decaying profile when the interfacial barrier strength increases. However, for the transport along the quadratic dispersion direction, the boundary between the retro Andreev reflection and specular Andreev reflection is ambiguous, and the differential conductance decays with increasing the momentum mismatch or the interfacial barrier strength. We illustrate the pseudo-spin textures to reveal the underling physics behind the anisotropic coherent transport properties. These results enrich the understanding of the superconducting coherent transport in semi-Dirac materials.

show abstract

“…Since the type-III is the critical point between the type-I and the type-II, one may have the following question: Can we understand the behavior of the type-III Dirac cones by taking the limit from the type-I or type-II? So far, electric and thermoelectric transports for tilted Dirac fermions, both the longitudinal and transverse ones, have been intensively studied [34][35][36][37][38][39]. However, previous works are mostly on continuous models, and the study on lattice models is limited.…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric transport of type-I, II, and III massless Dirac fermions in two-dimensional lattice model

Mizoguchi,

Matsuura,

Ogata

2021

Preprint

View full text Add to dashboard Cite

We study longitudinal electric and thermoelectric transport coefficients of Dirac fermions on a simple lattice model where tuning of a single parameter enables us to change the type of Dirac cones from type-I to type-II. We pay particular attention to the behavior of the critical situation, i.e., the type-III Dirac cone. We find that the transport coefficients of the type-III Dirac fermions behave neither the limiting case of the type-I nor type-II. On one hand, the qualitative behaviors of the type-III case are similar to those of the type-I. On the other hand, the transport coefficients do not change monotonically upon increasing the tilting, namely, the largest thermoelectric response is obtained not for the type-III case but for the optically tilted type-I case. For the optimal case, the sizable transport coefficients are obtained, e.g., the dimensionless figure of merit being 0.18.

show abstract

Quantum thermoelectrics based on two-dimensional semi-Dirac materials

Cited by 27 publications

References 37 publications

Graphene as a nanoelectromechanical reference piezoresistor

Graphene as a nanoelectromechanical reference piezoresistor

Anisotropic Andreev reflection in semi-Dirac materials

Thermoelectric transport of type-I, II, and III massless Dirac fermions in two-dimensional lattice model

Contact Info

Product

Resources

About