Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5

Mankowsky, Roman; Subedi, Alaska; Först, Michael; Mariager, S. O.; Chollet, Matthieu; Lemke, Henrik T.; Robinson, J. C.; Glownia, James M.; Minitti, Michael P.; Frañó, Alex; Fechner, Michael; Spaldin, Nicola A.; Loew, T.; Keimer, B.; Georges, Antoine; Cavalleri, Andrea

doi:10.1038/nature13875

Cited by 488 publications

(480 citation statements)

References 25 publications

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“…3. In these calculations, I have used a pump pulse with a symmetric Gaussian profile and a width of σ = 250 fs, which correspond to typical pump pulses used in midinfrared excitations [6,7,9]. A pump frequency of = 1.03 IR was used in the simulations, which is chosen to be slightly offresonance with the frequency of the Q IR mode to demonstrate that this method is efficacious even if the pump pulse is not precisely resonant with the Q IR mode.…”

Section: Resultsmentioning

confidence: 99%

“…Fourth, I find that the Q P mode has a strong Q 3 P order anharmonicity, which facilitates an abrupt switch of electric polarization as the Q IR amplitude is continuously increased. Coherent displacement along Raman mode coordinates utilizing nonlinear phonon couplings by resonantly exiting the highest frequency infrared mode of various centrosymmetric oxides has previously been demonstrated [6][7][8][9]. Therefore, the method proposed here to switch ferroelectric polarization at ultrafast time scales using midinfrared pulses is experimentally feasible.…”

Section: Introductionmentioning

confidence: 98%

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Proposal for ultrafast switching of ferroelectrics using midinfrared pulses

Subedi

2015

Phys. Rev. B

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I propose a method for ultrafast switching of ferroelectric polarization using midinfrared pulses. This involves selectively exciting the highest frequency A 1 phonon mode of a ferroelectric material with an intense midinfrared pulse. Large amplitude oscillations of this mode provides a unidirectional force to the lattice such that it displaces along the lowest frequency A 1 phonon mode coordinate because of a nonlinear coupling of the type gQ P Q 2 IR between the two modes. First-principles calculations show that this coupling is large in perovskite transition-metal oxide ferroelectrics, and the sign of the coupling is such that the lattice displaces in the switching direction. Furthermore, I find that the lowest frequency A 1 mode has a large Q 3 P order anharmonicity, which causes a discontinuous switch of electric polarization as the pump amplitude is continuously increased.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Proposal for ultrafast switching of ferroelectrics using midinfrared pulses

Subedi

2015

Phys. Rev. B

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“…On excitation with 0.18-eV pulses (blue curve), a gap appears that is reminiscent of superconductivity 103 . These experiments have motivated theoretical work, both to understand the nature of lattice dynamics arising from nonlinear phonon excitation, and to elucidate the possible origin of the superconducting enhancement 118,119 . The inset of Fig.…”

Section: Phononic Controls Of Quantum Materialsmentioning

confidence: 99%

“…At present, state-of-the-art ultrafast methods offer a near-complete characterization of the transient state 152 . Indeed, tr-ARPES provides a direct probe of the transient electronic structure 66,67,120,153 , tabletop and accelerator-based X-ray free-electron lasers readily capture momentary crystal arrangements 118,154 , nonlinear optical methods can directly interrogate the symmetries of quantum phases and their host lattices 30,[155][156][157][158] , while optical and soft X-ray techniques document electronic excitations, in some cases with elemental and orbital specificity 159 . Importantly, mesoscopic phenomena that are prevalent in quantum materials lead to new time and energy scales, as documented in various ultrafast studies 110,160 .…”

Section: Looking Into the Futurementioning

confidence: 99%

Towards properties on demand in quantum materials

2017

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Q uantum materials are on the ascent. This term embodies a vast portfolio of compounds and phenomena where ramifications of quantum mechanics are demonstrably real. Quantum materials are in the vanguard of contemporary physics in part because these systems afford an exceptional venue to uncover the many roles of symmetry, topology, dimensionality and strong correlations in macroscopic observables. Here we set out to explore the ways and means of creating new states of matter in quantum materials and manipulating their phases via external stimuli. Practical control of these properties is a precondition for exploiting quantum advantages in new photonic, electronic and energy technologies, a task of significant societal impact 1 . We will primarily focus on the following classes of quantum materials: transition metal oxides, Fe-and Cu-based high-T c superconductors, van der Waals semiconductors, topological insulators and Weyl semimetals, and, finally, graphene.The properties of quantum materials are anomalously sensitive to external stimuli. In these systems, interactions associated with spin, charge, lattice and orbital degrees of freedom are commonly on par with the electronic kinetic energy. A rather fragile balance between coexisting and competing ground states can be readily shifted via external stimuli, leading to a raft of quantum phases and transitions between them 2,3 . Furthermore, certain classes of driven quantum states (Fig. 1a and Box 1) are explicit products of coherent interaction between light and matter 4-6 . Alternatively, the properties of quantum materials can be pre-programmed by directly manipulating the electronic wavefunction and the attendant Berry phase that give rise to the anomalous velocity of electrons in a solid [7][8][9] . These complementary avenues of controls mean that investigations no longer need to be reduced to merely observing (in contrast, for example, to astrophysics). Instead, it is now feasible to attain, in a predictable fashion, 'properties on demand' by steering a quantum material towards a desirable ground, metastable or transient state. The past decade has witnessed an explosion in the field of quantum materials, headlined by the predictions and discoveries of novel Landau-symmetry-broken phases in correlated electron systems, topological phases in systems with strong spin-orbit coupling, and ultra-manipulable materials platforms based on two-dimensional van der Waals crystals. Discovering pathways to experimentally realize quantum phases of matter and exert control over their properties is a central goal of modern condensed-matter physics, which holds promise for a new generation of electronic/photonic devices with currently inaccessible and likely unimaginable functionalities. In this Review, we describe emerging strategies for selectively perturbing microscopic interaction parameters, which can be used to transform materials into a desired quantum state. Particular emphasis will be placed on recent successes to tailor electronic interaction parameters through th...

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“…Particularly intriguing is the case in which the laser intensity is so high that the usual harmonic approximation for the lattice dynamics breaks down and anharmonic phonon-phonon interactions become important. Recent experimental and theoretical studies [7,8] have clarified that quadratic-linear cubic coupling of the form Q 2 IR Q R between a driven infraredactive mode, Q IR , and a Raman-active mode, Q R , causes a shift in the equilibrium structure to a nonzero value of the Raman mode normal coordinates. This nonlinear phononic effect has most notably been associated with the observation of coherent transport, an indicator of superconductivity, far above the usual superconducting Curie temperature in underdoped YBaCu 3 O 6+δ [9][10][11].…”

mentioning

confidence: 99%

Ultrafast Structure Switching through Nonlinear Phononics

2017

Self Cite

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We describe an ultrafast coherent control of the transient structural distortion arising from nonlinear phononics in ErFeO3. Using density functional theory, we calculate the structural properties as input to an anharmonic phonon model that describes the response of the system to a pulsed optical excitation. We find that the trilinear coupling of two orthogonal infrared-active phonons to a Raman-active phonon causes a transient distortion of the lattice. The direction of the distortion is determined by the polarization of the exciting light, suggesting a route to nonlinear phononic lattice control and switching. Since the occurrence of the coupling is determined by the symmetry of the system we propose that it is a universal feature of orthorhombic and tetragonal perovskites.Over the last decade it has been shown repeatedly that laser excitation of infrared-active phonons is a powerful tool for modifying the properties of materials. This dynamical materials design approach has been used to drive metal-insulator transitions [1,2], to melt orbital order [3,4] and to induce superconductivity or modify superconducting transition temperatures [5,6] in a range of complex oxides. Particularly intriguing is the case in which the laser intensity is so high that the usual harmonic approximation for the lattice dynamics breaks down and anharmonic phonon-phonon interactions become important. Recent experimental and theoretical studies [7,8] have clarified that quadratic-linear cubic coupling of the form Q 2 IR Q R between a driven infraredactive mode, Q IR , and a Raman-active mode, Q R , causes a shift in the equilibrium structure to a nonzero value of the Raman mode normal coordinates. This nonlinear phononic effect has most notably been associated with the observation of coherent transport, an indicator of superconductivity, far above the usual superconducting Curie temperature in underdoped YBaCu 3 O 6+δ [9-11].Here we investigate theoretically a different kind of cubic phononic coupling of the trilinear form Q IR1 Q IR2 Q R , in which two different infrared-active (IR) modes are excited simultaneously and couple anharmonically to a single Raman mode. Our motivation is provided by recent experimental work on the perovskite-structure orthoferrite ErFeO 3 [12], in which two polar modes of similar frequencies with atomic displacement patterns along the inequivalent a and b orthorhombic axes were simultaneously excited. Ref. [12] reported and analyzed the resulting excitation of a magnon; here our focus is on the changes caused by and the implications of the nonlinear phonon dynamics.ErFeO 3 is a distorted perovskite with the orthorhombic P nma structure and the typical G-type antiferromagnetic ordering of the Fe 3+ magnetic moments [13] (Fig. 1). The primitive magnetic unit cell contains 20 atoms, resulting in 60 phonon modes characterised by representations (within the orthorhombic point group mmm) A g , B (1,2,3)g , A u and B (1,2,3)u . Of the polar "u" modes, only B 1u , B 2u and B 3u have dipole moments and are therefo...

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Nonlinear lattice dynamics as a basis for enhanced superconductivity in YBa2Cu3O6.5

Cited by 488 publications

References 25 publications

Proposal for ultrafast switching of ferroelectrics using midinfrared pulses

Proposal for ultrafast switching of ferroelectrics using midinfrared pulses

Towards properties on demand in quantum materials

Ultrafast Structure Switching through Nonlinear Phononics

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