Vanishing of interband light absorption in a persistent spin helix state

Zhou, Li; Marsiglio, F.; Ćarbotte, J. P.

doi:10.1038/srep02828

Cited by 34 publications

(23 citation statements)

References 38 publications

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“…This result is nontrivial: indeed, setting naively τ tr η ¼ τ in Eq. (8) would lead to [42] σ ≃ ðn − n 0 =2Þτ 0 =m, i.e., σ < σ Drude even at n > n 0 [47]. On the other hand, as the system enters the DSO regime τ starts to decrease linearly, as predicted by Eq.…”

mentioning

confidence: 70%

Unconventional dc Transport in Rashba Electron Gases

et al. 2016

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We discuss the transport properties of a disordered two-dimensional electron gas with strong Rashba spin-orbit coupling. We show that in the high-density regime where the Fermi energy overcomes the energy associated with spin-orbit coupling, dc transport is accurately described by a standard Drude's law, due to a nontrivial compensation between the suppression of backscattering and the relativistic correction to the quasiparticle velocity. On the contrary, when the system enters the opposite dominant spin-orbit regime, Drude's paradigm breaks down and the dc conductivity becomes strongly sensitive to the spin-orbit coupling strength, providing a suitable tool to test the entanglement between spin and charge degrees of freedom in these systems. DOI: 10.1103/PhysRevLett.116.166602 Spin-orbit (SO) coupling is a fundamental ingredient in spintronics [1], as it provides an advantageous locking between spin and electron orbital momentum. Recently, intense research efforts [2] have been devoted to twodimensional materials with broken inversion symmetry, where the SO strength, parametrized by a characteristic energy scale E 0 , can be tuned by means of external conditions (electric fields, gating, doping, pressure, strain, etc.). In most of these systems (for example, surface alloys [3][4][5][6][7][8][9], layered bismuth tellurohalides [10][11][12][13][14][15][16], HgTe quantum wells [17], and interfaces between complex oxides [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]) the total charge carrier density n can be tuned down to very small concentrations, implying very small Fermi energies E F . Although the high-density (HD) regime E F ≳ E 0 has been widely investigated [2,[33][34][35][36][37][38], relatively less attention has been paid to the opposite regime of dominant SO (DSO), E 0 ≳ E F .In this Letter we provide a detailed investigation of the dc conductivity of a 2D electron gas (2DEG) with Rashba [39] SO coupling in the different density regimes. Using a Boltzmann approach and a fully quantum analysis based on the Kubo formula, we show that in the high-density regime E F ≳ E 0 dc transport is independent of the SO strength, and the dc conductivity σ dc of electrons having effective mass m and scattering time τ 0 follows the conventional Drude law for 2DEGs,which results from a nontrivial cancellation of the SO coupling effects on the quasiparticle velocity and transport scattering time. Remarkably, as soon as the system enters the DSO regime E 0 ≳ E F , Drude's paradigm Eq. (1) breaks down and the dc conductivity accurately follows the analytical formula:where n 0 ¼ 2mE 0 =ðπℏ 2 Þ is the density at E F ¼ E 0 . In contrast to the linear dependence of σ dc on the charge density found in the HD regime, n ≥ n 0 , Eq. (2) predicts an unconventional nonlinear behavior of σ dc with n that is controlled by the SO interaction encoded in n 0 . The relevance of this result is twofold: demonstrating that dc transport is strongly sensitive to Rashba SO coupling, not only does it suggest that SO coupling cou...

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confidence: 70%

Unconventional dc Transport in Rashba Electron Gases

et al. 2016

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“…As we mentioned above, the massive (gapped) twodimension Dirac-system as well as the 2DEG and the parabolic system decay as r −2 for large distance, for massless (gapless) three-dimension Dirac or Weyl semimetal, the Friedel oscillation decay as r −4 due to the chirality effect which supress the back scattering in q = 2k F even in the low-temperature. While for the parabolic system with both the Rashba-coupling and the Dresselhaus-coupling in unequal strength (thus with the broken SU(2) symmetry), the doubly singularities occur [47] due to their effect to the interband transition [48].…”

Section: Friedel Oscillationmentioning

confidence: 99%

Dynamical polarization, plasmon model, and the Friedel oscillation of the screened potential in doped Dirac and Weyl system

Wu¹

2018

Preprint

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We discuss the dynamical polarization, plasmon dispersion, relaxation time, and the Friedel oscillation of screened potential of the two-dimension Dirac and threedimension Weyl system (which are gapped) in the low-energy tigh-binding model. The results, like the Fermi wavevector, Thomas-Fermi wavevector, and longitudinal conductivity are obtained in different dimensions. Some important conclusions are detailedly discussed in this paper, including the screening character under short or long range Coulomb interaction, and the longitudinal conductivity in two-or threedimensions. The longitudinal conductivity in optical limit is distinguishing for the case of two-dimension system and three-dimension system. The density-dependence (including the carrier density and the impurity concentration) of the Fermi wavevector, dc conductivity, and the relaxation time are discussed. Specially, for the doped Weyl system, the pumped carrier density due to the chiral anomaly origin from electromagnetic response is controlled by the internode relaxation time which has also been analyzed. Our results is helpful to the application of the Dirac or Weyl systems as well as the study on their low-temperature characters.

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“…This is quite different to the case of conventional graphene which is characterized by a broadband absorption caused by interband transitions. The suppression of interband absorption caused by the Fermi surface topology has been studied previously 40 . The detailed study of the interband absorption suppression in the considered geometry is the subject of the ongoing work.…”

Section: Conductivity Tensormentioning

confidence: 99%

Two-dimensional hyperbolic medium for electrons and photons based on the array of tunnel-coupled graphene nanoribbons

Trushkov

Iorsh

2015

Phys. Rev. B

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We study the electronic band structure and optical conductivity of an array of tunnel-coupled array of graphene nanoribbons. We show that due to the coupling of electronic edge states for the zigzag nanoribbon structure, the Fermi surface can become a hyperbola similarly to the case of the layered metal-dielectric structures, where the hyperbolic isofrequency contours originate from the coupling of localized surface plasmon polaritons. Moreover, we show that for both types of the ribbon edge, the optical response of the structure can be characterized by a uniaxial conductivity tensor, having principal components of the different signs. Therefore, the tunnel-coupled nanoribbon array can be regarded as a tunable hyperbolic metasurface.

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Vanishing of interband light absorption in a persistent spin helix state

Cited by 34 publications

References 38 publications

Unconventional dc Transport in Rashba Electron Gases

Unconventional dc Transport in Rashba Electron Gases

Dynamical polarization, plasmon model, and the Friedel oscillation of the screened potential in doped Dirac and Weyl system

Two-dimensional hyperbolic medium for electrons and photons based on the array of tunnel-coupled graphene nanoribbons

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