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Yu, Wing Yiu; Cheung, Yiu Wing; Saines, Paul J.; Imai, Masaki; Matsumoto, Takuya; Michioka, Chishiro; Yoshimura, Kazuyoshi; Goh, Swee K.

doi:10.1103/physrevlett.115.207003

Cited by 128 publications

(158 citation statements)

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“…Superconducting stannides [1,2] with stoichiometry A 3 T 4 Sn 13 (A = La, Sr, Ca and T = Co, Rh, Ir) have received a renewed attention owing to the discovery of a structural transition that can be tuned to 0 K [3][4][5]. In Sr 3 Ir 4 Sn 13 and Sr 3 Rh 4 Sn 13 , the structural transition occurs at T * 147 [3,6] and 138 K [4,7], respectively.…”

Section: Introductionmentioning

confidence: 99%

“…In Sr 3 Ir 4 Sn 13 and Sr 3 Rh 4 Sn 13 , the structural transition occurs at T * 147 [3,6] and 138 K [4,7], respectively. In these systems, a pronounced anomaly can be seen at T * in various physical properties [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17], including the electrical resistivity, the magnetic susceptibility and the specific heat. With applied pressure or the substitution of Sr by Ca, i.e., (Ca x Sr 1−x ) 3 Ir 4 Sn 13 and (Ca x Sr 1−x ) 3 Rh 4 Sn 13 , T * decreases rapidly, accompanied by a moderate increase in the superconducting transition temperature T c , which peaks near the composition/pressure where T * extrapolates to 0 K. The phase diagrams constructed thus highly resemble the ones constructed for many topical superconductors found in the vicinity of a magnetic quantum critical point [29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

“…In the vicinity of the putative structural quantum critical point where T * extrapolates to 0 K, μSR [22] and specific heat [5] detected a strongly enhanced electron-phonon coupling strength, indicated by the enhancement in 2 (0)/k B T c and C/γ T c beyond the BCS weak-coupling values [35][36][37], where (0) is the size of the gap, C is the specific heat jump at T c and γ is the Sommerfeld coefficient. [23,24].…”

Section: Introductionmentioning

confidence: 99%

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Second-order structural transition in the superconductorLa3Co4Sn13

et al. 2016

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The quasiskutterudite superconductor La 3 Co 4 Sn 13 undergoes a phase transition at T * = 152 K. By measuring the temperature dependence of heat capacity, electrical resistivity, and the superlattice reflection intensity using x rays, we explore the character of the phase transition at T * . Our lattice dynamic calculations found imaginary phonon frequencies around the M point when the high-temperature structure is used in the calculations, indicating that the structure is unstable at the zero-temperature limit. The combined experimental and computational results establish that T * is associated with a second-order structural transition with q = (0.5,0.5,0) (or the M point). Further electronic band structure calculations reveal Fermi surface sheets with low-curvature segments, which allow us to draw qualitative comparison with both Sr 3 Ir 4 Sn 13 and Sr 3 Rh 4 Sn 13 in which similar physics has been discussed recently.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Second-order structural transition in the superconductorLa3Co4Sn13

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“…Yet, in this case, it can easily be explained within the standard BCS-based theories: the gap associated with the CDW closes at the critical point, resulting in an increase of N ( F ), which, in turn, leads to an increase of the SC transition temperature T c . As a consequence, the dependence of T c on the tuning parameter is usually rather weak in the non-CDW regime beyond the critical point 16,17,[20][21][22][23] . There is currently no clear evidence that quantum critical fluctuations associated with the CDW QCP have any effect on the SC 24 .…”

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confidence: 99%

Charge density wave quantum critical point with strong enhancement of superconductivity

et al. 2017

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led to a great interest in QCPs are the very unusual properties that are observed near a QCP, such as unconventional superconductivity (SC), non-Fermi-liquid or anomalous critical behaviour 3-6 . Quantum fluctuations are therefore suspected to cause these anomalous properties, but most aspects are far from being understood and are still the subject of active discussions. An issue that has attracted great interest is the appearance of unconventional SC observed at magnetic QCPs, that is where a magnetic ordered state is suppressed. Such unconventional SC states have been reported for very different kinds of compounds, for example heavy-fermion systems 3,7 , cuprates 8,9 and iron pnictides 10,11 . There is some evidence that backs up the hypothesis that the binding of electrons into the superconducting Cooper pairs is not mediated by phononic excitations as in classical superconductors, but by magnetic excitations connected to the disappearing magnetic order 12,13 . The fact that SC is observed only in the vicinity of the QCP and presents a strong dependence on the tuning parameter supports this hypothesis. It often results in a dome-like shape of the phase diagram of tuning parameter versus temperature.However, QCPs are not restricted to magnetic systems; they can be associated with any continuous phase transition. While searching for appropriate non-magnetic systems that show a QCP with associated SC, we looked at compounds that show a charge density wave (CDW) type of structural transition. CDW systems present an instability of the electronic states close to the Fermi level F , which results in a modulation of the electronic charges below a transition temperature T CDW (ref. 14). The modulation periodicity is usually associated with a nesting vector of the Fermi surface. Therefore, a gap opens in the electronic density of states (DOS) at F , N ( F ), below T CDW . In one-dimensional (1D) systems, for which such a transition was initially proposed, this effect changes the character of the system from metallic for T > T CDW to insulating for T < T CDW . In 2D or 3D systems, the gap opens only on a part of the Fermi surface and, therefore, the conductivity remains metallic below T CDW . The opening of the gap does, however, lead to a very characteristic upturn of the resistivity ρ(T ) at T CDW .Some CDW transitions can be tuned to a T = 0 critical point as well [15][16][17][18][19][20][21] . The appearance or a strengthening of a superconducting state is frequently found near the vanishing point of the CDW state, similar to magnetic QCPs. Yet, in this case, it can easily be explained within the standard BCS-based theories: the gap associated with the CDW closes at the critical point, resulting in an increase of N ( F ), which, in turn, leads to an increase of the SC transition temperature T c . As a consequence, the dependence of T c on the tuning parameter is usually rather weak in the non-CDW regime beyond the critical point 16,17,[20][21][22][23] . There is currently no clear evidence that quantum critical fluc...

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“…Recent work on members of the stannide superconducting family A 3 T 4 Sn 13 (A = La,Sr,Ca; T = Ir,Rh) [5][6][7][8][9][10][11][12][13] is proving to be interesting in this context. Studies of Sr 3 Ir 4 Sn 13 have shown that the material undergoes a continuous second-order phase transition at a temperature T * ∼ 147 K, which is observed in a range of transport, spectroscopic, and thermodynamic measurements [14,15].…”

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confidence: 99%

Experimental determination of the Fermi surface ofSr3Ir4Sn13

et al. 2016

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The stannide family of materials A 3 T 4 Sn 13 (A = La,Sr,Ca; T = Ir,Rh) is interesting due to the interplay between a tunable lattice instability and phonon-mediated superconductivity with T c ∼ 5-7 K. In Sr 3 Ir 4 Sn 13 , a structural transition temperature T ∼ 147 K associated with this instability has been reported, which is believed to result from a superlattice distortion of the high-temperature phase on cooling. Here we report an experimental study of the electronic structure of a member of this material family, Sr 3 Ir 4 Sn 13 , through measurements of quantum oscillations and comparison with density functional theory calculations. Our measurements reveal good agreement with theory using the lattice parameters consistent with a body-centered-cubic lattice of symmetry I43d of the low-temperature phase. The study of the fermiology of Sr 3 Ir 4 Sn 13 that we present here should help inform models of multiband superconductivity in the superconducting stannides. DOI: 10.1103/PhysRevB.93.235121 Structural distortions of a crystal lattice can often profoundly influence electronic properties. In materials such as Ca 2 RuO 4 , for instance, tilt and rotations of the RuO 6 octahedra can induce a Mott insulating transition [1,2], while in the iron arsenide materials, modifications of the Fermi surface driven by structural distortions have been shown to play a role in enhancing superconductivity [3,4]. Understanding the subtle interplay between structural degrees of freedom and electronic and magnetic order remains a major research theme in condensed-matter physics.Recent work on members of the stannide superconducting family A 3 T 4 Sn 13 (A = La,Sr,Ca; T = Ir,Rh) [5-13] is proving to be interesting in this context. Studies of Sr 3 Ir 4 Sn 13 have shown that the material undergoes a continuous second-order phase transition at a temperature T * ∼ 147 K, which is observed in a range of transport, spectroscopic, and thermodynamic measurements [14,15]. Upon further cooling, superconductivity emerges with a transition temperature T c = 5 K [6,[16][17][18]. X-ray diffraction measurements suggest that T corresponds to a structural phase transition from the simple cubic I phase (P m3n) to the I phase [5,19], a body-centered-cubic lattice (I43d), with a corresponding doubling of the lattice constant.A remarkable feature of the A 3 T 4 Sn 13 system is its highly tunable nature. Isoelectronic substitution of Sr by Ca has the effect of applying chemical pressure, initially enhancing, then suppressing T c in a domelike fashion, an effect that is also seen by applying hydrostatic pressure [5,7]. At the same time, T is suppressed to zero, leading to a structural quantum phase transition with an associated softening of parts of the phonon spectrum [7]. While there is evidence that the lattice distortion is accompanied by the formation of a charge density wave (CDW) [5,15] which partially gaps out states at the Fermi level [14], there is no evidence of long-range magnetic order. This offers a rare opportunity to study supercondu...

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Strong Coupling Superconductivity in the Vicinity of the Structural Quantum Critical Point in(CaxSr1−x)

Cited by 128 publications

References 54 publications

Second-order structural transition in the superconductorLa3Co4Sn13

Second-order structural transition in the superconductorLa3Co4Sn13

Charge density wave quantum critical point with strong enhancement of superconductivity

Experimental determination of the Fermi surface ofSr3Ir4Sn13

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