Lattice Effects on Nematic Quantum Criticality in Metals

Paul, I.; Garst, Markus

doi:10.1103/physrevlett.118.227601

Cited by 79 publications

(124 citation statements)

References 38 publications

(50 reference statements)

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“…Although our model does not accurately describe the microscopics of any specific material and ignores physical effects that may be important (55)(56)(57)(58), it is plausible that the qualitative behavior proximate to the QCP is relatively insensitive to microscopic details. Our results bear striking similarities to the behavior seen in certain high-temperature superconductors: In several iron-based superconductors, the resistivity is anomalously large and T linear near the putative nematic QCP (36,59), and the fermionic spectral properties of our model in the critical regime are reminiscent of the nodal-antinodal dichotomy reported in the "strange metal" regime of certain cuprates (60,61).…”

Section: Discussionmentioning

confidence: 99%

Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point

Lederer

Schattner

Berg

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

192

158

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Using determinantal quantum Monte Carlo, we compute the properties of a lattice model with spin 1 2 itinerant electrons tuned through a quantum phase transition to an Ising nematic phase. The nematic fluctuations induce superconductivity with a broad dome in the superconducting Tc enclosing the nematic quantum critical point. For temperatures above Tc, we see strikingly nonFermi liquid behavior, including a "nodal-antinodal dichotomy" reminiscent of that seen in several transition metal oxides. In addition, the critical fluctuations have a strong effect on the lowfrequency optical conductivity, resulting in behavior consistent with "bad metal" phenomenology.superconductivity | non-Fermi liquid | quantum criticality U pon approach to a quantum critical point (QCP), the correlation length, ξ, associated with order parameter fluctuations diverges; consequently microscopic aspects of the physics are averaged out and certain properties of the system are universal. Asymptotically close to criticality, exact theoretical predictions concerning the scaling behavior of some measurable quantities are possible. However, in solids, it is rarely possible to convincingly access asymptopia; there are few experimentally documented cases in which a thermodynamic susceptibility grows as a function of decreasing temperature, T , in proportion to a single power law χ ∼ T −x over significantly more than one decade of magnitude. This is particularly true of metallic QCPs, where the metallic critical point may be preempted by the occurrence of a superconducting dome, a fluctuation-driven first-order transition, or some other catastrophe.However, there is a looser sense in which a QCP can serve as an organizing principle for understanding properties of solids over a range of parameters: In the "neighborhood" of a QCP, where χ is large (in natural units) and ξ is more than a few lattice constants, it is reasonable to conjecture that quantum critical fluctuations play a significant role in determining the properties of the material and that, at least on a qualitative level, those properties may be robust (i.e., not strongly dependent on microscopic details), even if they are not universal.With this in mind, we carried out extensive numerical "experiments" on a simple 2D lattice model of itinerant electrons coupled to an Ising-like "nematic" order parameter field, Eq. 1. By varying a parameter in the Hamiltonian, h, the system can be tuned through a quantum or thermal transition from a disordered (symmetric) phase to a nematic phase that spontaneously breaks the lattice symmetry from C4 to C2. Related models of nematic quantum criticality have been studied extensively (1-27), using various analytic methods, and can also be studied with minus-sign-free determinantal quantum Monte Carlo (DQMC) (28-30). Recent Monte Carlo studies have examined the scaling structure of nematic and related QCPs (31, 32) as well as the role of fluctuations in promoting superconductivity (33,34). Moreover, the model is particularly topical, as there is good evide...

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Section: Discussionmentioning

confidence: 99%

Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point

Lederer

Schattner

Berg

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

192

158

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“…S2(g-i). This could be due to additional constrains to be included either to account for the nematoelastic coupling [29] and/or the effect of impurities. For example, a very dirty sample of FeSe 1−x S x close to x nom ∼ 0.18 was recently suggested to obey H − T scaling [30].…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, near a antiferromagnetic critical point in the presence of spin fluctuations the impurity level also affects the temperature exponent [36]. Furthermore, the scale at which the crossover to Fermi liquid behavior occurs at T F L in nematic critical systems could depend on the strength of the coupling to the lattice [29].…”

Section: Resultsmentioning

confidence: 99%

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Bristow

Reiss

Haghighirad

et al. 2020

Phys. Rev. Research

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Understanding superconductivity requires detailed knowledge of the normal electronic state from which it emerges. A nematic electronic state that breaks the rotational symmetry of the lattice can potentially promote unique scattering relevant for superconductivity. Here, we investigate the normal transport of superconducting FeSe1−xSx across a nematic phase transition using high magnetic fields up to 69 T to establish the temperature and field-dependencies. We find that the nematic state is an anomalous non-Fermi liquid, dominated by a linear resistivity at low temperatures that can transform into a Fermi liquid, depending on the composition x and the impurity level. Near the nematic end point, we find an extended temperature regime with ∼ T 1.5 resistivity. The transverse magnetoresistance inside the nematic phase has as a ∼ H 1.55 dependence over a large magnetic field range and it displays an unusual peak at low temperatures inside the nematic phase. Our study reveals anomalous transport inside the nematic phase, driven by the subtle interplay between the changes in the electronic structure of a multi-band system and the unusual scattering processes affected by large magnetic fields and disorder.Magnetic field is a unique tuning parameter that can suppress superconductivity to reveal the normal low-temperature electronic behavior of many unconventional superconductors [1,2]. High-magnetic fields can also induce new phases of matter, probe Fermi surfaces and determine the quasi-particle masses from quantum oscillations in the proximity of quantum critical points [1,3]. In unconventional superconductors, close to antiferromagnetic critical regions, an unusual scaling between a linear resistivity in temperature and magnetic fields was found [4,5]. Magnetic fields can also induce metal-toinsulator transitions, as in hole-doped cuprates, where superconductivity emerges from an exotic electronic ground state [2].FeSe is a unique bulk superconductor with T c ∼ 9 K which displays a variety of complex and competing electronic phases [6]. FeSe is a bad metal at room temperature and it enters a nematic electronic state below T s ∼ 87 K. This nematic phase is characterized by multi-band shifts driven by orbital ordering that lead to Fermi surface distortions [6,7]. Furthermore, the electronic ground state is that of a strongly correlated system and the quasiparticle masses display orbital-dependent enhancements [7,8]. FeSe shows no long-range magnetic order at ambient pressure, but complex magnetic fluctuations are present at high energies over a large temperature range [9]. Below T s , the spin-lattice relaxation rate from NMR experiments is enhanced as it captures the low-energy tail of the stripe spin-fluctuations [10,11]. Furthermore, recent µSR studies invoke the close proximity of FeSe to a magnetic quantum critical point as the muon relaxation rate shows unusual temperature dependence inside the nematic state [12].The changes in the electronic structure and magnetic fluctuations of FeSe can have profound implicatio...

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“…The 40 Zr isotopes have been recently the subject of several experimental investigations [9][10][11][12][13][14][15] and theoretical studies, including mean-field based methods [16][17][18], the Monte-Carlo shell-model (MCSM) [19] and algebraic methods [8,20]. We adapt here the algebraic approach of the Interacting Boson Model (IBM) [21], with bosons representing valence nucleon pairs counted from the nearest closed shells.…”

Section: The Ibm With Configuration Mixing In the Zr Chainmentioning

confidence: 99%

Intertwined quantum phase transitions in the Zr isotopes

2019

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We present a detailed analysis of spectra and other observables for the entire chain of Zr isotopes, from neutron number 52 to 70, in the framework of the interacting boson model with configuration mixing. The results suggest a remarkable interplay of multiple quantum phase transitions (QPTs).One type of QPT involves an abrupt crossing of normal and intruder configurations, superimposed on a second type of QPT involving gradual shape-changes within each configuration.

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Lattice Effects on Nematic Quantum Criticality in Metals

Cited by 79 publications

References 38 publications

Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point

Superconductivity and non-Fermi liquid behavior near a nematic quantum critical point

Anomalous high-magnetic field electronic state of the nematic superconductors FeSe1−xSx

Intertwined quantum phase transitions in the Zr isotopes

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