Limits...
The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors.

Hinton JP, Thewalt E, Alpichshev Z, Mahmood F, Koralek JD, Chan MK, Veit MJ, Dorow CJ, Barišić N, Kemper AF, Bonn DA, Hardy WN, Liang R, Gedik N, Greven M, Lanzara A, Orenstein J - Sci Rep (2016)

Bottom Line: We find that τqp(T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field.We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below.Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

View Article: PubMed Central - PubMed

Affiliation: Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

ABSTRACT
In the underdoped copper-oxides, high-temperature superconductivity condenses from a nonconventional metallic "pseudogap" phase that exhibits a variety of non-Fermi liquid properties. Recently, it has become clear that a charge density wave (CDW) phase exists within the pseudogap regime. This CDW coexists and competes with superconductivity (SC) below the transition temperature Tc, suggesting that these two orders are intimately related. Here we show that the condensation of the superfluid from this unconventional precursor is reflected in deviations from the predictions of BSC theory regarding the recombination rate of quasiparticles. We report a detailed investigation of the quasiparticle (QP) recombination lifetime, τqp, as a function of temperature and magnetic field in underdoped HgBa2CuO(4+δ) (Hg-1201) and YBa2Cu3O(6+x) (YBCO) single crystals by ultrafast time-resolved reflectivity. We find that τqp(T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field. We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below. Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

No MeSH data available.


Related in: MedlinePlus

Doping dependence of onset temperature.(a–f) The temperature dependence of ΔR(t = 1 ps)/R is plotted for a series of doping levels. Values of Tonset as determined from the inflection points of the curves are indicated by the vertical blue arrows, and Tc is indicated by red arrows. (g) Tonset as function of hole concentration, p, as obtained from the inflection points in (a–f) are plotted as blue squares in a T − p phase diagram for the Hg-1201 system. Also shown is the onset temperature of charge order observed by X-ray scattering12 (green circle) and the critical temperatures for superconductivity (open circles).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4829850&req=5

f2: Doping dependence of onset temperature.(a–f) The temperature dependence of ΔR(t = 1 ps)/R is plotted for a series of doping levels. Values of Tonset as determined from the inflection points of the curves are indicated by the vertical blue arrows, and Tc is indicated by red arrows. (g) Tonset as function of hole concentration, p, as obtained from the inflection points in (a–f) are plotted as blue squares in a T − p phase diagram for the Hg-1201 system. Also shown is the onset temperature of charge order observed by X-ray scattering12 (green circle) and the critical temperatures for superconductivity (open circles).

Mentions: In Fig. 2a–f we plot the maximum value of ΔR/R(t) (which occurs at ≈1 ps after photoexcitation) as a function of T in underdoped Hg-1201 samples with Tc’s ranging from 55 to 91 K. The temperature (Tonset) at which the positive component of ΔR appears is indicated by a blue down arrow in each panel. Note that ΔR continues to increase continuously with further decrease of T, without a clear feature at the critical temperature for superconductivity (indicated by red arrows). Both Tonset and Tc are plotted as a function of hole concentration, p, in Fig. 2g. The onset temperatures of positive ΔR outline a dome that peaks on the underdoped side of the phase diagram and extends to temperatures 130 K above Tc.


The rate of quasiparticle recombination probes the onset of coherence in cuprate superconductors.

Hinton JP, Thewalt E, Alpichshev Z, Mahmood F, Koralek JD, Chan MK, Veit MJ, Dorow CJ, Barišić N, Kemper AF, Bonn DA, Hardy WN, Liang R, Gedik N, Greven M, Lanzara A, Orenstein J - Sci Rep (2016)

Doping dependence of onset temperature.(a–f) The temperature dependence of ΔR(t = 1 ps)/R is plotted for a series of doping levels. Values of Tonset as determined from the inflection points of the curves are indicated by the vertical blue arrows, and Tc is indicated by red arrows. (g) Tonset as function of hole concentration, p, as obtained from the inflection points in (a–f) are plotted as blue squares in a T − p phase diagram for the Hg-1201 system. Also shown is the onset temperature of charge order observed by X-ray scattering12 (green circle) and the critical temperatures for superconductivity (open circles).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829850&req=5

f2: Doping dependence of onset temperature.(a–f) The temperature dependence of ΔR(t = 1 ps)/R is plotted for a series of doping levels. Values of Tonset as determined from the inflection points of the curves are indicated by the vertical blue arrows, and Tc is indicated by red arrows. (g) Tonset as function of hole concentration, p, as obtained from the inflection points in (a–f) are plotted as blue squares in a T − p phase diagram for the Hg-1201 system. Also shown is the onset temperature of charge order observed by X-ray scattering12 (green circle) and the critical temperatures for superconductivity (open circles).
Mentions: In Fig. 2a–f we plot the maximum value of ΔR/R(t) (which occurs at ≈1 ps after photoexcitation) as a function of T in underdoped Hg-1201 samples with Tc’s ranging from 55 to 91 K. The temperature (Tonset) at which the positive component of ΔR appears is indicated by a blue down arrow in each panel. Note that ΔR continues to increase continuously with further decrease of T, without a clear feature at the critical temperature for superconductivity (indicated by red arrows). Both Tonset and Tc are plotted as a function of hole concentration, p, in Fig. 2g. The onset temperatures of positive ΔR outline a dome that peaks on the underdoped side of the phase diagram and extends to temperatures 130 K above Tc.

Bottom Line: We find that τqp(T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field.We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below.Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

View Article: PubMed Central - PubMed

Affiliation: Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

ABSTRACT
In the underdoped copper-oxides, high-temperature superconductivity condenses from a nonconventional metallic "pseudogap" phase that exhibits a variety of non-Fermi liquid properties. Recently, it has become clear that a charge density wave (CDW) phase exists within the pseudogap regime. This CDW coexists and competes with superconductivity (SC) below the transition temperature Tc, suggesting that these two orders are intimately related. Here we show that the condensation of the superfluid from this unconventional precursor is reflected in deviations from the predictions of BSC theory regarding the recombination rate of quasiparticles. We report a detailed investigation of the quasiparticle (QP) recombination lifetime, τqp, as a function of temperature and magnetic field in underdoped HgBa2CuO(4+δ) (Hg-1201) and YBa2Cu3O(6+x) (YBCO) single crystals by ultrafast time-resolved reflectivity. We find that τqp(T) exhibits a local maximum in a small temperature window near Tc that is prominent in underdoped samples with coexisting charge order and vanishes with application of a small magnetic field. We explain this unusual, non-BCS behavior by positing that Tc marks a transition from phase-fluctuating SC/CDW composite order above to a SC/CDW condensate below. Our results suggest that the superfluid in underdoped cuprates is a condensate of coherently-mixed particle-particle and particle-hole pairs.

No MeSH data available.


Related in: MedlinePlus