Coherence effects in the low-temperature Hall coefficient of the heavy-fermion system<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">UPd</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">Al</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mm

Huth, Michael; Hessert, J.; Jourdan, Martin; Kaldowski, A.; Adrian, H.

doi:10.1103/physrevb.50.1309

Cited by 9 publications

(4 citation statements)

References 27 publications

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“…4). The first was also observed in earlier measurements on UPd 2 Al 3 (0 0 1) thin films, where the field was applied parallel to [0 0 1], current also along [1 0 0] [7]. The second feature was present but much weaker in these previous measurements.…”

supporting

confidence: 62%

Electronic properties of *-oriented thin films

Foerster

Jourdan

Zakharov

et al. 2007

Journal of Magnetism and Magnetic Materials

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supporting

confidence: 62%

Electronic properties of *-oriented thin films

Foerster

Jourdan

Zakharov

et al. 2007

Journal of Magnetism and Magnetic Materials

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“…1 and known from literature. [4,33,34] This can be described as ρ dc = ρ 0 + AT 2 , where A = 2.3 · 10 −7 Ωcm/K 2 , similar to previous studies. [35,36] Such a quadratic temperature dependence is usually taken as an indicator for Fermi-liquid behavior, which should lead to a characteristic frequency dependence of the relaxation rate as well.…”

Section: Frequency-dependent Relaxation Ratementioning

confidence: 53%

Microwave conductivity of heavy fermions in UPd2Al3

2010

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Abstract. Heavy-fermion compounds are characterized by electronic correlation effects at low energies which can directly be accessed with optical spectroscopy. Here we present detailed measurements of the frequency-and temperature-dependent conductivity of the heavy-fermion compound UPd2Al3 using broadband microwave spectroscopy in the frequency range 45 MHz to 40 GHz at temperatures down to 1.7 K.We observe the full Drude response with a relaxation time up to 50 ps, proving that the mass enhancement of the heavy charge carriers goes hand in hand with an enhancement of the relaxation time. We show that the relaxation rate as a function of temperature scales with the dc resistivity. We do not find any signs of a frequency-dependent relaxation rate within the addressed frequency range. PACS

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“…a) The Hall coefficient in the zero-temperature limit, remarkably large in URu 2 Si 2 (R H ∼ 10 −8 m 3 /C corresponding to 0.05 carriers per U in a simple one-band picture [14,25]), exceeds by a factor of twenty the same quantity in UPd 2 Al 3 [26]. Note that neither multi-band effects (which would eventually reduce the total R H ) or skew scattering (estimated in the zero-temperature limit using the Pauli susceptibility [25]) can explain the magnitude of R H in URu 2 Si 2 .…”

mentioning

confidence: 99%

“…Moreover, by comparing the physical properties of URu 2 Si 2 and UPd 2 Al 3 at low temperatures, one finds three independent lines of evidence suggesting that the carrier density in the former is one order of magnitude smaller than the latter. a) The Hall coefficient in the zero-temperature limit, remarkably large in URu 2 Si 2 (R H ∼ 10 −8 m 3 /C corresponding to 0.05 carriers per U in a simple one-band picture [14,25]), exceeds by a factor of twenty the same quantity in UPd 2 Al 3 [26]. Note that neither multi-band effects (which would eventually reduce the total R H ) or skew scattering (estimated in the zero-temperature limit using the Pauli susceptibility [25]) can explain the magnitude of R H in URu 2 Si 2 .…”

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confidence: 99%

Thermal Transport in the Hidden-Order State ofURu2Si2

et al. 2005

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We present a study of thermal conductivity in the normal state of the heavy-fermion superconductor URu2Si2. Ordering at 18K leads to a steep increase in thermal conductivity and (in contrast with all other cases of magnetic ordering in heavy-fermion compounds) to an enhancement of the Lorenz number. By linking this observation to several other previously reported features, we conclude that most of the carriers disappear in the ordered state and this leads to a drastic increase in both phononic and electronic mean-free-path.PACS numbers: 72.15. Eb, 71.27.+a, 63.20.Kr Over the years, the phase transition which occurs at T 0 ∼ 18 K in URu 2 Si 2 has become a notorious enigma of Heavy-Fermion(HF) physics. This phase transition is associated with a large jump in heat capacity [1,2,3] similar to the one observed in several anti-ferromagnetically ordered HF compounds. On the other hand, and in contrast with the latter, the magnetic moment in the ordered state appears to be very weak(∼ 0.03µ B /U) [4]. Such a small magnetic moment is a feature found in many HF compounds. The puzzle of URu 2 Si 2 resides in this unique combination. This is the only case of ordering by heavy electrons with large anomalies in all macroscopic properties leading to a tiny magnetic moment.In order to resolve this apparent paradox, many models have been proposed [5,6,7,8,9,10,11]. It is widely suspected that there is a hidden order parameter[12] distinct from the weak antiferromagnetism. Several exotic orders have been imagined [5,6,9,10]. More recently, a feature in the 29 Si NMR data has provided support for electronic phase separation in the hidden-order state [13]. The debate has been mostly focused on the unusual thermodynamic properties of this ordering. The challenge for the theory has been to identify the degrees of freedom corresponding to the huge amount of entropy lost in the transition. Transport properties have not attracted a comparable attention. However, as indicated by the recent observation of a very large Nernst effect in the hidden-order state [14], they may prove to contain interesting information.In this paper, we report on a study of thermal conductivity in URu 2 Si 2 that detects a notable difference between this compound and all other HF systems which order anti-ferromagneically. The distinct signature of this phase transition in thermal transport is a steep increase in the Lorenz number at the onset of transition. After checking the validity of the Wiedemann-Franz law in the ordered state, we will argue that results support a scenario in which most of the electronic carriers vanish and this leads to an increase in the mean-freepath of both surviving quasi-particles and heat-carrying phonons. Thus, the consequences of this phase transition on thermal transport are strikingly similar to the well-known case of the superconducting transition in the high-T c cuprates.This observation highlights the drastic decrease in the carrier density induced by the hidden order leads in URu 2 Si 2 , which becomes one order of magnit...

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Coherence effects in the low-temperature Hall coefficient of the heavy-fermion systemUPd2Al3

Cited by 9 publications

References 27 publications

Electronic properties of *-oriented thin films

Electronic properties of *-oriented thin films

Microwave conductivity of heavy fermions in UPd2Al3

Thermal Transport in the Hidden-Order State ofURu2Si2

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