Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu<sub>2</sub>Si<sub>2</sub> and Its Alloys Probed by the dHvA Effect

Aoki, Haruyoshi; Kimura, Noriaki; Terashima, Taichi

doi:10.7566/jpsj.83.072001

Cited by 32 publications

(24 citation statements)

References 201 publications

(372 reference statements)

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“…But the signature of electronic instabilities can be followed continuously with clear anomalies. The aim of this paper is to present a complete study of the TEP in the Ising-type heavy fermion compound CeRu 2 Si 2 , where a FS change under magnetic field is already well established by de Haas-van Alphen (dHvA) experiments [12][13][14][15]. CeRu 2 Si 2 crystallizes in the tetragonal ThCr 2 Si 2 -type structure.…”

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confidence: 97%

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

et al. 2014

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We report field-and temperature-dependent measurements of the thermoelectric power (TEP) across the pseudometamagnetic transition (MMT) in CeRu 2 Si 2 . We applied the thermoelectric gradient parallel and perpendicular to the field along the c axis of the tetragonal crystal which is the easy magnetization axis. At the MMT at H m = 7.8 T, a strong anomaly in the TEP is observed for both configurations with opposite signs. The anomaly at H m becomes a cascade of anomalies at very low temperature which seems to be a generic feature of the TEP at a change in the topology of the Fermi surface (FS) in heavy Fermion multiband systems. Simultaneously, quantum oscillations in the magnetic field dependence of the TEP are observed for both configurations below and above the MMT.During two decades, magnetic quantum phase transitions (QPT) from antiferromagnetic (AF) or ferromagnetic (FM) phases to paramagnetic (PM) ground states have been discussed mainly in the Doniach frame [1] or in the picture of the itinerant spin fluctuations [2]. These approaches neglect the possibility of a Fermi surface (FS) reconstruction at the QPT. However, in some heavy-fermion compounds a FS reconstruction has been shown directly by quantum oscillations experiments. Prominent examples are the AF compounds CeRh 2 Si 2 [3] and CeRhIn 5 [4], where the evolution of the FS has been studied as a function of pressure through their magnetic quantum critical points. The rapid change of the Hall coefficient in the heavy-fermion compound YbRh 2 Si 2 as a function of field through the critical field H c , where the antiferromagnetic order is suppressed, has been also interpreted as a signature of FS reconstruction [5,6]. These observations led to the development of unconventional models such as the breakdown of Kondo effect at the QPT [7]. The emerging picture is that a variation from a small FS to a large FS through the critical pressure P c or the critical magnetic field H c in AF systems can be observed near the magnetic quantum criticality [8].However, an unambiguous proof of a FS change and furthermore its complete determination by quantum oscillation experiments or angle-resolved-photo-emission spectroscopy is often very difficult. Thus, a confirmation requires a convergence of various macroscopic and microscopic measurements. Among them the thermoelectric power (TEP) is a very powerful probe as it is linked to the energy ( ) derivative of the electrical conductivity σ ( ) at low temperature [9]:Thus, the TEP is directly related to the derivative of the density of states N ( ). The strength of the TEP to detect * Email address: alexandre.pourret@cea.fr FS singularities has been demonstrated clearly three decades ago on simple metals notably in the study of Lifshitz transitions [10] which are topological transitions of the FS. They do not break any symmetry and appear as a crossover at finite temperature, but will be quantum phase transitions at T = 0. In multiband systems like heavy fermion compounds the TEP response is complex. The thermoelectric re...

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confidence: 97%

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

et al. 2014

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“…Fig.S2 compares the variation of A with Fermi energy in SrTiO3- with other Fermi liquids in which a quadratic resistivity has been observed and the structure of the Fermi surface is experimentally known. The list includes two heavy-electron metals [UPt3 (31,32) and CeRu2Si2 (33,34)in which all components of the Fermi surface have been observed], two oxides [Sr2RuO4 (22,35) and La1.7Sr0.3CuO4 (23)] and three semi-metals [bismuth (36,37), Bi0.96Sb0.04 (38)(39)(40) and graphite (41)(42)(43) and]. Table S3 details the reported value of frequency of quantum oscillations and cyclotron mass used to extract the Fermi energy using EF= (ћkF) 2 /2m*.…”

Section: T-square Resistivity In Nb-doped and La-doped Samplesmentioning

confidence: 99%

Scalable T ² resistivity in a small single-component Fermi surface

Lin

Fauqué

Behnia

2015

Science

124

193

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Scattering among electrons generates a distinct contribution to electrical resistivity that follows a quadratic temperature dependence. In strongly-correlated electron systems, the prefactor A of this T 2 resistivity scales with the magnitude of the electronic specific heat, . Here, we show that one can change the magnitude of A by four orders of magnitude in metallic SrTiO3by tuning the concentration of the carriers and consequently, the Fermi energy. The T 2 behavior persists in the single-band dilute limit despite the absence of two known mechanisms for T 2 behavior, distinct electron reservoirs and Umklapp processes. The results highlight the absence of a microscopic theory for momentum decay through electron-electron scattering in different Fermi liquids. Main Text: Warming a metal enhances its resistivity because with increasing temperature (T)scattering events along the trajectory of a charge-carrying electron become more frequent. In most simple metals the dominant mechanism is scattering by phonons leading to a T 5 dependence of resistivity. In 1937, Baber identified electron-electron scattering as the origin of T 2 resistivity observed in many transition metals (1). During the last few decades it has been firmly established that, at low temperatures, resistivity () in a Fermi liquid follows a quadratic temperature dependence expressed as =0+AT 2 and that correlations among electrons enhance both A and the electronic specific heat, . This is often expressed through the Kadowaki-Woods ratio (2-6), RKW=A/ 2 , which link two distinct properties of a Fermi liquid, each set by the same material-dependent Fermi energy, EF.The Pauli exclusion principle is the ultimate reason behind both the T-linear specific heat and Tsquare resistivity in Fermi liquids. Electrons that give rise to both properties are those confined to a width of kBT/EF, where kB is the Boltzmann constant. In the case of resistivity, this is true of both electrons participating in the scattering event, hence the exponent of two. However, electron-electron scattering alone does not generate a finite contribution to resistivity, because such a scattering event would conserve momentum with no decay in the charge current. The presence of an underlying lattice is required in any scenario for generating T 2 resistivity from electron-electron scattering. Dimensional considerations imply:Here, ħ and e are fundamental constants and lquad is a material-dependent length scale, which can be set either by the Fermi wave-length of electrons, or by the interatomic distance or a combination of both. Mott argued that the average distance between two scattering events is proportional to the concentration and the collision cross section of electronscs (7). Therefore:Here, kF is the Fermi wave-vector and cs is set by the specific process governing the decay in charge current due to the presence of lattice.There are several types of theoretical proposals for generating T 2 resistivity from electronelectron scattering in the presence of a lattice...

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“…We notice that the factor 10 between the γ values is related to the ratio of their relevant energies, then we can compare their TEP response taking into account this factor 10 in temperature analysis.. Figure 12 shows the longitudinal and transverse TEP responses of CeRu 2 Si 2 at 290 mK by comparison to the CeRh 2 Si 2 ones at 3 K. At H m in CeRu 2 Si 2 a drastic change of the FS has been reported 3,29,30 and is associated with a strong increase of A and γ right at H m preserving a quasi constant Comparing to UCoAl that presents a first order metamagnetic transition from PM to FM, we notice that a sharp change of S at the transition also occurs in this compound 31 . Thus, the TEP signal in CeRh 2 Si 2 at H c is clearly governed by the strong first order nature of the metamagnetic transition while the FS crossover detected at H m in CeRu 2 Si 2 is characteristic of a sole Lifshitz transition.…”

Section: Discussionmentioning

confidence: 99%

“…H m can be interpreted as a crossover continuation of the metamagnetic field H c 2,27,28 . Expanding the volume via La or Ge dopings leads to recover AF long range order and first order metamagnetism under magnetic field 2,3 . We will focus here on the difference in magnetic response of the undoped pure lattice.…”

Section: Discussionmentioning

confidence: 99%

“…This is characteristic of a polarized paramagnetic phase with a FS quite different from the PM ones. Up to now, the CeRu 2 Si 2 series is the fingerprint example of these phenomena 2,3 . Here we present the effects of H an P on the thermoelectric power (TEP) of the compound CeRh 2 Si 2 with the aim to observe the response on a system where a FS instability under pressure is well established by previous de Haas van Alphen (dHvA) experiments [4][5][6] and where the magnetic structure of the AF phase has been fully determined 7 .…”

Section: Introductionmentioning

confidence: 99%

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Fermi surface instabilities inCeRh2Si2at high magnetic field and pressure

et al. 2015

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We present thermoelectric power (TEP) studies under pressure and high magnetic field in the antiferromagnet CeRh2Si2 at low temperature. Under magnetic field, large quantum oscillations are observed in the TEP, S(H), in the antiferromagnetic phase. They suddenly disappear when entering in the polarized paramagnetic (PPM) state at Hc pointing out an important reconstruction of the Fermi surface (FS). Under pressure, S/T increases strongly of at low temperature near the critical pressure Pc, where the AF order is suppressed, implying the interplay of a FS change and low energy excitations driven by spin and valence fluctuations. The difference between the TEP signal in the PPM state above Hc and in the paramagnetic state (PM) above Pc can be explained by different FS. Band structure calculations at P = 0 stress that in the AF phase the 4f contribution at the Fermi level (EF ) is weak while it is the main contribution in the PM domain. By analogy to previous work on CeRu2Si2, in the PPM phase of CeRh2Si2 the 4f contribution at EF will drop.

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Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu₂Si₂ and Its Alloys Probed by the dHvA Effect

Cited by 32 publications

References 201 publications

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

Scalable T ² resistivity in a small single-component Fermi surface

Fermi surface instabilities inCeRh2Si2at high magnetic field and pressure

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Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu2Si2 and Its Alloys Probed by the dHvA Effect

Cited by 32 publications

References 201 publications

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

Lifshitz transition and metamagnetism: Thermoelectric studies ofCeRu2Si2

Scalable T 2 resistivity in a small single-component Fermi surface

Fermi surface instabilities inCeRh2Si2at high magnetic field and pressure

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Fermi Surface Properties, Metamagnetic Transition and Quantum Phase Transition of CeRu₂Si₂ and Its Alloys Probed by the dHvA Effect

Scalable T ² resistivity in a small single-component Fermi surface