Evidence for a connection between charge density waves and the pressure enhancement of superconductivity in 2H-NbSe2

Berthier, Y.; Molinié, P.; Jérôme, D.

doi:10.1016/0038-1098(76)90986-8

Cited by 143 publications

(74 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…boson ph exc (6) Notice that ph is the renormalized phonon energy, which already includes the effect of particle-hole fluctuations, and which would correspond to the experimentally observed mode if no excitons were present [the dashed line in Fig. 6(a)].…”

Section: Hybrid Phonon-exciton Modelmentioning

confidence: 99%

Superconductivity and hybrid soft modes inTiSe2

et al. 2016

View full text Add to dashboard Cite

show abstract

Section: Hybrid Phonon-exciton Modelmentioning

confidence: 99%

Superconductivity and hybrid soft modes inTiSe2

et al. 2016

View full text Add to dashboard Cite

show abstract

“…This selfconsistent, cooperative organization between local and itinerant spins is analogous to the interplay of lattice distortions and charge in phonon-mediated CDWs. Most SDWs and CDWs are highly susceptible to pressure 11,12 . However, the stability and evolution of the itinerant magnetic order as the separation between local moments is tuned in this new type of SDW has not been explored.…”

mentioning

confidence: 99%

Hidden one-dimensional spin modulation in a three-dimensional metal

et al. 2014

View full text Add to dashboard Cite

Pressure can transform a transparent material into an opaque one, quench the moments in a magnet and force solids to flow like liquids. At 15 GPa, the pressure found 500 km below the earth's surface, the semiconductors silicon and germanium superconduct. Yet, at this same pressure, we show here that the magnetism in metallic GdSi remains completely robust even as it shrinks by one-seventh of its volume. Non-resonant X-ray magnetic diffraction in a specially designed diamond anvil cell, combined with band structure calculations, reveal the stability of the incommensurate spin density wave, which can be traced to a persistently nested portion of the Fermi surface that becomes increasingly onedimensional under pressure. A cooperative interaction between nested, itinerant spins and local magnetic moments provides the organizing principle for the modulated magnetic order, salient both for its insights into the role of topology in ordered states and its potential functionality.

show abstract

“…However, long-wavelength CDW amplitude modes affect the superconductivity by modulating the total density of states at the Fermi surface (17,22,23). The established pressure-temperature (P-T) phase diagram (17,24) is summarized in Fig. 2A.…”

mentioning

confidence: 99%

“…The electron and hole states that condense into the CDW comprise only 1% of the total density of states at the Fermi surface (18,19,21) and both the CDW order parameter amplitude and its static phase coherence length ξ s are unaffected when the superconductivity is suppressed in a high magnetic field (16), suggesting that the superconducting state has minimal effect on CDW pairing. However, long-wavelength CDW amplitude modes affect the superconductivity by modulating the total density of states at the Fermi surface (17,22,23). The established pressure-temperature (P-T) phase diagram (17, 24) is summarized in Fig.…”

mentioning

confidence: 99%

“…NbSe 2 is a model two-dimensional CDW system (15)(16)(17)(18)(19)(20)(21) where negatively charged electrons and positively charged holes form a spatially periodic arrangement below the transition temperature T CDW ¼ 33.5 K (15-21). NbSe 2 also superconducts below T sc ¼ 7.2 K, and the electronic band structure supports both the CDW and superconductivity with some competition for electronic states (16,22,23).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Order parameter fluctuations at a buried quantum critical point

Feng

Wang

Jaramillo

et al. 2012

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

View full text Add to dashboard Cite

Quantum criticality is a central concept in condensed matter physics, but the direct observation of quantum critical fluctuations has remained elusive. Here we present an X-ray diffraction study of the charge density wave (CDW) in 2H-NbSe 2 at high pressure and low temperature, where we observe a broad regime of order parameter fluctuations that are controlled by proximity to a quantum critical point. X-rays can track the CDW despite the fact that the quantum critical regime is shrouded inside a superconducting phase; and in contrast to transport probes, allow direct measurement of the critical fluctuations of the charge order. Concurrent measurements of the crystal lattice point to a critical transition that is continuous in nature. Our results confirm the long-standing expectations of enhanced quantum fluctuations in low-dimensional systems, and may help to constrain theories of the quantum critical Fermi surface.incommensurate electronic state | transition metal dichalcogenides | diffraction line shapes | diamond anvil cell A continuous change of phase often involves critical fluctuations that destabilize one phase in favor of another. These fluctuations characterize the nature of the phase transition, but can be difficult to measure directly. This difficulty is especially acute in broad classes of materials with quantum phase transitions (1, 2), from colossal magnetoresistance manganites (3) to heavy fermion and cuprate superconductors (4, 5) to archetypal, metallic ferromagnets (6, 7), where strong interactions can cut off the critical behavior via a structural instability, or competing ground states can shroud the quantum critical point.Charge and spin density wave (CDW/SDW) systems have been shown to be good candidates for experimental studies of quantum critical behavior, where fluctuations disrupt electron pairing and restore the metallic Fermi surface (8, 9). In these systems the interaction strengths are weaker than in strongly correlated materials, reducing the likelihood of strong first-order transitions and allowing experimental access to the quantum critical point. Recent low-temperature studies of the SDW transition in bulk, elemental Cr under pressure demonstrated a continuous quantum phase transition in an antiferromagnetic metal (10, 11), but the quantum fluctuation regime deduced via transport measurements was very narrow. Stronger fluctuations over a broader range are expected in systems with lower electronic dimensionality. Moreover, quantum criticality in two-dimensional layered systems with predilections for density wave distortions has received sustained interest due to the observation of density wave pairing in the high-T C superconductors (12-14). Here we present a low-temperature and high-pressure synchrotron X-ray diffraction study of the two-dimensional CDW system 2H-NbSe 2 , where scattering from the incommensurate charge order is possible even deep within the coexisting superconducting ground state. Our results demonstrate a wide regime of spatial fluctuations of the CDW order par...

show abstract

Evidence for a connection between charge density waves and the pressure enhancement of superconductivity in 2H-NbSe2

Cited by 143 publications

References 20 publications

Superconductivity and hybrid soft modes inTiSe2

Superconductivity and hybrid soft modes inTiSe2

Hidden one-dimensional spin modulation in a three-dimensional metal

Order parameter fluctuations at a buried quantum critical point

Contact Info

Product

Resources

About