Browsing by Author "Muñoz, Enrique"
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- Item¡Defendamos Díchato! Bienes comunes y conflicto territorial en los espacios litorales chilenos(2017) Camus, Pablo; Hidalgo, Rodrigo; Pérez Bustamante, Leonel; Muñoz, Enrique
- ItemElectromagnetic coupling and transport in a topological insulator-graphene hetero-structure(2023) Bonilla Moreno, Daniel; Castaño Yepes, J.D.; Martín Ruiz, A.; Muñoz, EnriqueThe electromagnetic coupling between hetero-structures made of different materials is of great interest, both from the perspective of discovering new phenomena, as well as for its potential applications in novel devices. In this work, we study the electromagnetic coupling of a hetero-structure made of a topological insulator (TI) slab and a single graphene layer, where the later presents a diluted concentration of ionized impurities. We explore the topological effects of the magneto-electric polarizability (MEP) of the TI, as well as its relative dielectric permittivity on the electrical conductivity in graphene at low but finite temperatures. Copyright © 2023, The Authors. All rights reserved.
- ItemElectromagnetic coupling and transport in a topological insulator–graphene heterostructure(2023) Bonilla Moreno, Daniel; Castaño Yepes, Jorge David; Martín Ruiz, A.; Muñoz, EnriqueThe electromagnetic coupling between heterostructures made of different materials is of great interest, both from the perspective of discovering new phenomena, as well as for its potential applications in novel devices. In this work, we study the electromagnetic coupling of a heterostructure made of a topological insulator (TI) slab and a single graphene layer, where the later presents a diluted concentration of ionized impurities. We explore the topological effects of the magnetoelectric polarizability of the TI, as well as its relative dielectric permittivity on the electrical conductivity in graphene at low but finite temperatures.
- ItemElectronic Transport in Weyl Semimetals with a Uniform Concentration of Torsional Dislocations(2022) Bonilla Moreno, Daniel; Muñoz, EnriqueIn this article, we consider a theoretical model for a type I Weyl semimetal, under the presence of a diluted uniform concentration of torsional dislocations. By means of a mathematical analysis for partial wave scattering (phase-shift) for the T-matrix, we obtain the corresponding retarded and advanced Green’s functions that include the effects of multiple scattering events with the ensemble of randomly distributed dislocations. Combining this analysis with the Kubo formalism, and including vertex corrections, we calculate the electronic conductivity as a function of temperature and concentration of dislocations. We further evaluate our analytical formulas to predict the electrical conductivity of several transition metal monopnictides, i.e., TaAs, TaP, NbAs, and NbP.
- Itemζ-function for a model with spectral dependent boundary conditions(2025) Falomir, Horacio; Loewe, Marcelo; Muñoz, Enrique; Rojas Gómez-Lobo, Juan CristóbalWe explore the meromorphic structure of the zeta-function associated with the boundary eigenvalue problem of a modified Sturm-Liouville operator subject to spectral-dependent boundary conditions at one end of a segment of length l. We find that it presents isolated simple poles that follow the general rule valid for second-order differential operator subject to standard local boundary conditions. We employ our results to evaluate the determinant of the operator and the Casimir energy of the system it describes, and study its dependence on l for both the massive and the massless cases.
- ItemQuantum transport across a slab of a type I Weyl Semimetal with a uniform concentration of torsion dislocation defects(2023) Bonilla Moreno, Daniel; Muñoz, EnriqueIn this work, we study the electronic transport in a Type I Weyl Semimetal slab with a uniform and diluted concentration of torsional dislocation defects. The defects have cylindrical geometry and are modeled as a pseudo-gauge field accounting for torsional strain and a repulsive delta-shell potential for the lattice mismatch effect. We give explicit forms for the retarded Green function in the presence of uniformly distributed scattering centers and the spectral density in terms of the relaxation time (imaginary part of the self-energy). The relaxation time is computed from the known scattering cross-section as a function of the phase shifts for the single-defect scattering problem. Finally, we use the Kubo formula to calculate electrical conductivity.
- ItemTemperature fluctuations in a relativistic gas: Pressure corrections and possible consequences in the deconfinement transition(2024) Castaño Yepes, Jorge David; Loewe, Marcelo; Muñoz, Enrique; Rojas Gómez-Lobo, Juan CristóbalIn this work, we study the effects of random temperature fluctuations on the partition function of a quantum system by means of the replica method. This picture provides a conceptual model for a quantum nonequilibrium system, depicted as an ensemble of subsystems at different temperatures, randomly distributed with respect to a given mean value. We then assume the temperature displays stochastic fluctuations T ¼ T0 þ δT with respect to its ensemble average value T0, with zero mean standard deviation δT ¼0 and δT2 ¼ Δ. By means of the replica method, we obtain the average grand canonical potential, leading to the equation of state and the corresponding excess pressure caused by these fluctuations with respect to the equilibrium system at a uniform temperature. Our findings reveal an increase in pressure as the system’s ensemble average temperature T0 rises, consistently exceeding the pressure observed in an equilibrium state. We applied our general formalism to three paradigmatic physical systems; the relativistic Fermi gas, the ideal gas of photons, and a gas of non-Abelian gauge fields (gluons) in the noninteracting limit. Finally, we explore the implications for the deconfinement transition in the context of the simple bag model, where we show that the critical temperature decreases.
- ItemThermo-Magneto-Electric Transport through a Torsion Dislocation in a Type I Weyl Semimetal(2021) Bonilla Moreno, Daniel; Muñoz, Enrique; Soto Garrido, RodrigoHerein, we study electronic and thermoelectric transport in a type I Weyl semimetal nanojunction, with a torsional dislocation defect, in the presence of an external magnetic field parallel to the dislocation axis. The defect is modeled in a cylindrical geometry, as a combination of a gauge field accounting for torsional strain and a delta-potential barrier for the lattice mismatch effect. In the Landauer formalism, we find that due to the combination of strain and magnetic field, the electric current exhibits chiral valley-polarization, and the conductance displays the signature of Landau levels. We also compute the thermal transport coefficients, where a high thermopower and a large figure of merit are predicted for the junction.
- ItemThermoelectric transport in Weyl semimetals under a uniform concentration of torsional dislocations(2024) Bonilla Moreno, Daniel Alejandro; Muñoz, EnriqueIn this article, we present an effective continuum model for a Weyl semimetal, to calculate its thermal and thermoelectric transport coefficients in the presence of a uniform concentration of torsional dislocations.We model each dislocation as a cylindrical region of finite radius a, where the corresponding elastic strain is described as a gauge field leading to a local pseudo-magnetic field. The transport coefficients are obtained by a combination of scattering theory, Green's functions and the Kubo formulae in the linear response regime. We applied our theoretical results to predict the electrical and thermal conductivities as well as the Seebeck coefficient for several transition metal monopnictides, i.e. TaAs, TaP, NbAs and NbP.