Interfaces in coexisting metals and Mott insulators

Lee, Juho; Yee, Chuck-Hou

doi:10.1103/physrevb.95.205126

Cited by 8 publications

(10 citation statements)

References 40 publications

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“…The second sound is usually characterized by a speed v ss , which can be calculated in the hydrodynamic limit as [16,21],…”

Section: Dynamics Of Second Sound Propagationmentioning

confidence: 99%

“…percentages. This effect is often neglected in previous theoretical discussions of second sound in graphitic materials [16,21] and shall be kept in mind in the future experimental detection.…”

Section: Impact Of Intrinsic Resistive Scatteringmentioning

confidence: 99%

“…In terms of the theoretical study, the window conditions of the two main phonon hydrodynamic phenomena: the steady-state phonon Poiseuille flow and transient second sound, have been well formulated for the graphene [16], other two-dimensional materials [15,20] and graphite [17]. The dispersion relation of second sound in single-wall carbon nanotube has been derived in the limit of only normal process (hydrodynamic limit) [21]. Furthermore, the detailed dynamics (including temperature and heat flux profiles) and thermal transport resistance of both in-plane (i.e.…”

Section: Introductionmentioning

confidence: 99%

“…The single mode relaxation time (SMRT) approximation is known to much underestimate the thermal conductivity of graphene due to the collective effect of phonon normal process [15,26]. In contrast, the Callaway's dual relaxation model [27] represents a better approximation to the full scattering term of PBE and is widely used in modeling and analyzing hydrodynamic phonon transport in graphitic materials [17,18,[21][22][23][24]28,29]. For transient heat transport cases, the solution of PBE with the ab initio full scattering term is extremely challenging and is not available in the literature to the author's best knowledge.…”

Section: Introductionmentioning

confidence: 99%

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Direct simulation of second sound in graphene by solving the phonon Boltzmann equation via a multiscale scheme

et al. 2019

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The direct simulation of the dynamics of second sound in graphitic materials remains a challenging task due to lack of methodology for solving the phonon Boltzmann equation in such a stiff hydrodynamic regime. In this work, we aim to tackle this challenge by developing a multiscale numerical scheme for the transient phonon Boltzmann equation under Callaway's dual relaxation model which captures well the collective phonon kinetics. Comparing to traditional numerical methods, the present multiscale scheme is efficient, accurate and stable in all transport regimes attributed to avoiding the use of time and spatial steps smaller than the relaxation time and mean free path of phonons. The formation, propagation and composition of ballistic pulses and second sound in graphene ribbon in two classical paradigms for experimental detection are investigated via the multiscale scheme. The second sound is declared to be mainly contributed by ZA phonon modes, whereas the ballistic pulses are mainly contributed by LA and TA phonon modes. The influence of temperature, isotope abundance and ribbon size on the second sound propagation is also explored. The speed of second sound in the observation window is found to be at most 20 percentages smaller than the theoretical value in hydrodynamic limit due to the finite umklapp, isotope and edge resistive scattering. The present study will contribute to not only the solution methodology of phonon Boltzmann equation, but also the physics of transient hydrodynamic phonon transport as guidance for future experimental detection.

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“…The second sound is usually characterized by a speed v ss , which can be calculated in the hydrodynamic limit as [16,21],…”

Section: Dynamics Of Second Sound Propagationmentioning

confidence: 99%

Section: Impact Of Intrinsic Resistive Scatteringmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Direct simulation of second sound in graphene by solving the phonon Boltzmann equation via a multiscale scheme

et al. 2019

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“…A simple approximation to describe this experimentally observed paramagnetic Mott insulating state, theoretically predicted to exist in a range of U between the paramagnetic metal and the 120 • Néel ordered state [38,39], is the DMFT [29,40]. This approach can be generalized to the inhomogeneous case [41][42][43][44][45][46][47][48][49][50]. Here we assume the DW lattice structure to be predetermined and fixed, and we focus on the effects of such a deformation on the electronic degrees of freedom.…”

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confidence: 99%

Mottness collapse without metallization in the domain wall of the triangular-lattice Mott insulator1T−TaS2

2019

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1T-TaS 2 is a charge-density-wave (CDW) compound with a Mott-insulating ground state. The metallic state obtained by doping, substitution or pulsed charge injection is characterized by an emergent CDW domain wall network, while single domain walls can be found in the pristine Mott state. Here we study whether and how the single walls become metallic. Tunneling spectroscopy reveals partial suppression of the Mott gap and the presence of in-gap states strongly localized at the domain-wall sites. Using the real-space dynamical mean field theory description of the strongly correlated quantum-paramagnet ground state we show that the local gap suppression follows from the increased hopping along the connected zigzag chain of lattice sites forming the domain wall, and that full metallisation is preempted by the splitting of the quasiparticle band into bonding and antibonding sub-bands due to the structural dimerization of the wall, explaining the presence of the in-gap states and the low density of states at the Fermi level.The interplay between superconductivity (SC) and correlated insulating phases, such as Mott insulators and charge density waves (CDW), is one of the central problems in condensed-matter physics. Remarkably, their combination can be found even in simple material systems, such as transition metal dichalcogenide (TMD) van der Waals compound 1T-TaS 2 . The ground state is a Mott insulator[1-3] with CDW[4] and unconventional quantum spin liquid behavior [5][6][7][8][9][10]. Upon Se substitution[11], Fe intercalation [12], or by applying pressure[13] it becomes superconducting, with both CDW and correlated behavior still present. Further control over electronic properties is possible through non-equilibrium charge injection via ultrafast optical or electrical pulses [14][15][16][17][18][19][20][21], which lead to drastic insulator to metastable metal transition. The long-standing hypothesis for metallisation and SC onset is linked to the formation of CDW domain walls, seen in multiple TMDs with different techniques [22][23][24]. Recently, it was challenged experimentally with scanning tunneling spectroscopy (STS) [25], which showed the absence of metallisation in certain types of walls. First-principles calculations revealed that atomic reconstruction in the walls may cause the formation of bound states[25] and band reconstruction [24], but the correlation effects were left out of scope. Thus, the crucial question of whether the CDW distortion inside the wall can lead to Mottness collapse remains open. In this paper we combine STS and dynamical mean field theory (DMFT) calculations to study the behavior of the Mott gap in CDW domain walls, finding Mottness collapse without metallisation.In 1T-TaS 2 , each layer is periodically modulated to form a √ 13 × √ 13 superlattice of David star deformations [4], resulting in a commensurate CDW state with a single half-filled electron band at the Fermi level [26,27]. The Coulomb repulsion opens a charge gap in this band, resulting in a Mott insulating ground state [2...

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Hydrodynamic Phonon Transport Perpendicular to Diffuse-Gray Boundaries

Yang

Yue

Liao

2018

Nanoscale and Microscale Thermophysical Engineering

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In this paper, we examine the application of an ideal phonon-hydrodynamic material as the heat transfer medium between two diffuse-gray boundaries with a finite temperature difference. We use the integral-equation approach to solve a modified phonon Boltzmann transport equation with the displaced Bose-Einstein distribution as the equilibrium distribution between two boundaries perpendicular to the heat transfer direction. When the distance between the boundaries is smaller than the phonon normal scattering mean free path, our solution converges to the ballistic limit as expected. In the other limit, we find that, although the local thermal conductivity in the bulk of the hydrodynamic material approaches infinity, the thermal boundary resistance at the interfaces becomes dominant. Our study provides insights to both the steady-state thermal characterization of phonon-hydrodynamic materials and the practical application of phonon-hydrodynamic materials for thermal management.

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Interfaces in coexisting metals and Mott insulators

Cited by 8 publications

References 40 publications

Direct simulation of second sound in graphene by solving the phonon Boltzmann equation via a multiscale scheme

Direct simulation of second sound in graphene by solving the phonon Boltzmann equation via a multiscale scheme

Mottness collapse without metallization in the domain wall of the triangular-lattice Mott insulator1T−TaS2

Hydrodynamic Phonon Transport Perpendicular to Diffuse-Gray Boundaries

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