Controlling competing orders via nonequilibrium acoustic phonons: Emergence of anisotropic effective electronic temperature

Schütt, Michael; Orth, Peter P.; Levchenko, Alex; Fernandes, Rafael M.

doi:10.1103/physrevb.97.035135

Cited by 15 publications

(9 citation statements)

References 50 publications

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“…These branch and wavevector-dependent phonon temperatures have their counterparts for the electronic states at different regions of the Fermi surface as observed experimentally by Schutt et al [45]. Then, by using the conservation of total energy and the Boltzmann kinetic theory, a set of coupled equations of motion for the temperatures of each phonon mode Q and of the electrons can be derived:…”

Section: Microscopic Out-of-equilibrium Dynamics Modelmentioning

confidence: 76%

Theory of out-of-equilibrium electron and phonon dynamics in metals after ultrafast laser excitation

Ritzmann,

Oppeneer,

Maldonado

2019

Preprint

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The out-of-equilibrium dynamics of electrons and phonons upon laser excitation are often described by the two-temperature model, which assumes that both subsystems are separately in thermal equilibrium. However, recent experiments show that this description is not sufficient to describe the out-of-equilibrium dynamics on ultrashort timescales. Here, we extend and apply a parameterfree microscopic out-of-equilibrium model to describe the ultrafast laser-induced system dynamics of archetypical metallic systems such as gold, aluminum, iron, nickel, and cobalt. We report strong deviations from the two-temperature model on the picosecond timescale for all the materials studied, even for those where the assumption of separate thermal equilibriums seemed less restrictive, like in gold. Furthermore, we demonstrate the importance of the phonon-mode dependent electronphonon coupling for the relaxation process and reveal the significance of this channel in the lattice equilibration through an indirect coupling between phonons via the electronic system.

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Section: Microscopic Out-of-equilibrium Dynamics Modelmentioning

confidence: 76%

Theory of out-of-equilibrium electron and phonon dynamics in metals after ultrafast laser excitation

Ritzmann,

Oppeneer,

Maldonado

2019

Preprint

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“…[10][11][12] Like in the two-band model we investigate here, our method can be very useful in cases where an exact solution is not (yet) available, for example, to investigate quenches towards more exotic fully gapped pairing states such as s + is or s + id. Other interesting future directions are to include a finite intraband pairing interaction r = 0, competing electronic order parameters such as spin-density waves, 55 or generalize and apply our Laplace method to study quenches in superconductors with a nodal gap structure such as those with d-wave symmetry. 56 we have Υ (∆, y)…”

Section: Damped Gap Oscillations In the Long-time Limitmentioning

confidence: 99%

Postquench gap dynamics of two-band superconductors

et al. 2019

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Recent experimental progress in the fields of cold quantum gases and ultrafast optical spectroscopy of quantum materials allows to controllably induce and probe non-adiabatic dynamics of superconductors and superfluids. The time-evolution of the gap function before relaxation with the lattice is determined by the superposition of coherently evolving individual Cooper pairs within the manifold of the Bardeen-Cooper-Schrieffer (BCS) wavefunction. While dynamics following an abrupt quench of the pairing interaction strength in the single-band BCS model has been exactly solved due to the integrability of the model, the dynamics of post-quench multi-band superconductors remain under scrutiny. Here, we develop a generalization of the Volkov-Kogan Laplace-space perturbative method that allows us to determine the non-adiabatic gap dynamics of two-band fully gapped superconductors for a wide range of quench amplitudes. Our approach expands the long-time dynamics around the steady-state asymptotic value of the gap, which is self-consistently determined, rather than around the equilibrium value of the gap. We explicitly demonstrate that this method recovers the exact solution of the long-time gap dynamics in the single-band case and perfectly agrees with a numerical solution of the two-band model. We discover that dephasing of Cooper pairs from different bands leads to faster collisionless relaxation of the gap oscillation with a power-law of t −3/2 instead of the well-known t −1/2 behavior found in the single-band case. Furthermore, the gap oscillations display beating patterns arising from the existence of two different asymptotic gap values. Our results have important implications to a variety of two-band superconductors driven out of equilibrium, such as iron-based superconductors, MgB2, and SrTiO3. arXiv:1908.06125v1 [cond-mat.supr-con]

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“…Nonlinear phononics allows an ultrafast (on subpicosecond time scales) dynamical control of the sample material properties. This is an example of what is called dynamical material design, see recent works and references therein [2][3][4][5][6][7][8][9]. The central mechanism is an infrared (IR) mode excited by terahertz-frequency optical pulses and anharmonically coupled to the Raman (R) mode.…”

Section: Introductionmentioning

confidence: 99%

Quantum heat engine based on dynamical materials design

2020

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We propose a novel type of quantum heat engine with functionality based on dynamical material design: the swift dynamical control of the magnetic properties of a chromium oxide Cr2O3 which we exploit as a working substance. We use density functional theory for the calculation of the magnetic and electronic properties of Cr2O3 and determine the time-dependent exchange coupling strengths. Exact diagonalization of the effective spin Hamiltonian yields the spin excitation spectrum which we use to construct the quantum heat engine and calculate its efficiency, the output power, the irreversible work, and the non-equilibrium work fluctuations. For the sake of completeness, we also consider a working substance composed of several unit cells. We show that even without an implementation of transitionless (adiabatic) driving the quantum friction is very low compared to the total produced work, which is an advantage of our working substance, as experimentally hard-to-implement adiabatic shortcuts are not necessary. Moreover, the working body shows some remarkable thermodynamic features due to the quantumness of the system.

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Controlling competing orders via nonequilibrium acoustic phonons: Emergence of anisotropic effective electronic temperature

Cited by 15 publications

References 50 publications

Theory of out-of-equilibrium electron and phonon dynamics in metals after ultrafast laser excitation

Theory of out-of-equilibrium electron and phonon dynamics in metals after ultrafast laser excitation

Postquench gap dynamics of two-band superconductors

Quantum heat engine based on dynamical materials design

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