Onset of the vortexlike Nernst signal above<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi>T</mml:mi></mml:mrow><mml:mrow><mml:mi>c</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:math>in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">La</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn><mml:mi>−</mml:mi><mml:mi>x</mml:mi></mml:mrow></mml:msub></mml:mrow><mml:mrow

Wang, Yayu; Xu, Zhu-An; Kakeshita, T.; Uchida, S.; Ono, Shimpei; Ando, Yoichi; Ong, N. P.

doi:10.1103/physrevb.64.224519

Cited by 325 publications

(325 citation statements)

References 23 publications

Supporting

Mentioning

288

Contrasting

Unclassified

Order By: Relevance

“…86 The sign of the Nernst coefficient ϑ does not change with the sign of µ and is thus an even function of µ. This is because both σ xy α xx and σ xx α xy , which appear in the numerator of the expression for ϑ in Eq.…”

Section: A Nernst Effect In a Linearized Dirac Hamiltonianmentioning

confidence: 89%

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Sharma¹,

Goswami²,

Tewari³

2016

Phys. Rev. B

177

187

View full text Add to dashboard Cite

Weyl semimetals (WSM) are topologically protected three dimensional materials whose low energy excitations are linearly dispersing massless Dirac fermions, possessing a non-trivial Berry curvature. Using semiclassical Boltzmann dynamics in the relaxation time approximation for a lattice model of time reversal (TR) symmetry broken WSM, we compute both magnetic field dependent and anomalous contributions to the Nernst coefficient. In addition to the magnetic field dependent Nernst response, which is present in both Dirac and Weyl semimetals, we show that, contrary to previous reports, the TR-broken WSM also has an anomalous Nernst response due to a non-vanishing Berry curvature. We also compute the thermal conductivities of a WSM in the Nernst (∇T ⊥ B) and the longitudinal (∇T B) set-up and confirm from our lattice model that in the parallel set-up, the Wiedemann-Franz law is violated between the longitudinal thermal and electrical conductivities due to chiral anomaly.

show abstract

Section: A Nernst Effect In a Linearized Dirac Hamiltonianmentioning

confidence: 89%

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Sharma¹,

Goswami²,

Tewari³

2016

Phys. Rev. B

177

187

View full text Add to dashboard Cite

show abstract

“…More generally, one of the most remarkable features of the pseudo-gap phenomena is the existence of effects of superconducting fluctuations, detectable 77,78,79 for instance in the Nernst signal, over a surprisingly broad range of temperatures and doping concentrations. At a broad-brush level 80 , these phenomena are a consequence of a phase stiffness scale that is small compared to the pairing scale.…”

Section: B Speculationsmentioning

confidence: 99%

Theory of the striped superconductor

2009

View full text Add to dashboard Cite

We define a distinct phase of matter, a pair density wave (PDW), in which the superconducting order parameter, φ( r, r ′ ), varies periodically as a function of position such that when averaged over the center of mass position, ( r + r ′ )/2, all components of φ vanish identically. Specifically, we study the simplest, unidirectional PDW, the "striped superconductor," which we argue may be at the heart of a number of spectacular experimental anomalies that have been observed in the failed high temperature superconductor, La2−xBaxCuO4. We present a solvable microscopic model with strong electron-electron interactions which supports a PDW groundstate. We also discuss, at the level of Landau theory, the nature of the coupling between the PDW and other order parameters, and the origins and some consequences of the unusual sensitivity of this state to quenched disorder. I. A NEW PHASE OF MATTERSuperconductivity which arises from the pairing of electrons in time reversed states is well understood as a weak coupling "Fermi surface" instability -a consequence of arbitrarily weak effective attractive interactions. 1 In this paper we explore a new type of superconducting state, a "pair density wave" (PDW), which is a distinct state of matter, and which does not occur under generic circumstances in the weak coupling limit -it requires interactions in excess of a critical strength. The PDW spontaneously breaks the global gauge symmetry, in precisely the same way as a conventional superconductor does. Thus, the order parameter is a charge 2e complex scalar field, φ. However, it also spontaneously breaks some of the translational and point group symmetries of the host crystal, in the same way as a conventional charge-density wave (CDW). In a PDW, for fixed r − r ′ , the order parameteris a periodic function of the center of mass coordinate, R ≡ ( r + r ′ )/2. Here, ψ † σ ( r) is the electron creation operator at position r with spin polarization σ. We will focus on the case in which translational symmetry is broken only in one direction, i.e. a unidirectional PDW or equivalently a "striped superconductor."Accompanying the PDW there is, as we will show below, induced CDW order with half the period of the PDW. However, the PDW differs from a state of coexisting superconducting and CDW order 2 , which has also been previously called a "pair-density wave". 3 Unlike the pair-density-wave state of Ref.[2], the average value of the superconducting order parameter vanishes for the PDW state we discuss here. This is a defining symmetry property of this state. The PDW is more closely analogous to the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state 5 which arises, under appropriate circumstances, when the electron gas is partially polarized by an applied magnetic field. However, explicit time-reversal symmetry breaking is an essential ingredient of the FFLO state, and is responsible for lifting the degeneracy ("nesting") between time-reversed pairs of quasiparticle states. In the absence of quenched disorder, the PDW state preserves time-r...

show abstract

“…8(b) [83]. In thin films of 4 He, the corresponding region exists above the superfluid temperature T c = T KT up to the "mean-field" superfluid energy scale whose upper limit can be given by the lambda transition temperature 2.2 K of the bulk 4 He.…”

Section: B Nernst Effectmentioning

confidence: 99%

“…The inset illustrates the proposal of microscopic phase separation between superconducting and normal metal regions in the overdoped region [79]. (b) The region of the Nernst effect, shown in the T -x phase diagram for LSCO [83]. The result of Tonset for the x = 0.10 sample is plotted with the green star symbol in Fig.…”

mentioning

confidence: 99%

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Uemura¹

2004

J. Phys.: Condens. Matter

123

View full text Add to dashboard Cite

To find out a primary determing factor of Tc and a pairing mechanism in high-Tc cuprates, we combine the muon spin relaxation results on ns/m * (superconducting carrier density / effective mass), accumulated over the last 15 years, with the results from neutron and Raman scattering, STM, specific heat, Nernst effect and ARPES measurements. We identify the neutron magnetic resonance mode as an analogue of roton minimum in the superfluid 4 He, and argue that ns/m * and the resonance mode energy ωres play a primary role in determining Tc in the underdoped region. We propose a picture that roton-like excitations in the cuprates appear as a coupled mode, which has the resonance mode for spin and charge responses at different momentum transfers but the same energy transfers, as detected respectively, by the neutron S=1 mode and the Raman S=0 A1g mode. We shall call this as the "hybrid spin/charge roton". After discussing the role of dimensionality in condensation, we propose a generic phase diagram of the cuprates with spatial phase separation in the overdoped region as a special case of the BE-BCS crossover conjecture where the superconducting coupling is lost rapidly in the overdoped region. Using a microscopic model of charge motion resonating with antiferomagnetic spin fluctuations, we propose a possibility that the hybrid spin/charge roton and higher-energy spin fluctuations mediate the superconducting pairing. In this model, the resonance modes can be viewed as a meson-analogue and the "dome" shape of the phase diagram can be understood as a natural consequence of departure from the competing Mott insulator ground state via carrier doping.

show abstract

Onset of the vortexlike Nernst signal aboveTcinLa2−x

Cited by 325 publications

References 23 publications

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Theory of the striped superconductor

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Contact Info

Product

Resources

About

Onset of the vortexlike Nernst signal aboveTcinLa2−x

Cited by 325 publications

References 23 publications

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Nernst and magnetothermal conductivity in a lattice model of Weyl fermions

Theory of the striped superconductor

Condensation, excitation, pairing, and superfluid density in high-Tc superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing

Contact Info

Product

Resources

About

Condensation, excitation, pairing, and superfluid density in high-T_c superconductors: the magnetic resonance mode as a roton analogue and a possible spin-mediated pairing