Order parameter fluctuations at a buried quantum critical point

Abstract

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-NbSe2 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 longstanding expectations of enhanced quantum fluctuations in low dimensional systems, and may help to constrain theories of the quantum critical Fermi surface.

to be published in PNAS

References in corpus (6)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Hidden Magnetism and Quantum Criticality in the Heavy Fermion Superconductor CeRhIn5
• Quantum phase transitions of metals in two spatial dimensions: II. Spin density wave order
• Two energy gaps and Fermi surface 'arcs' in NbSe2
• Phase separation and suppression of critical dynamics at quantum transitions of itinerant magnets: MnSi and (Sr${}_{1-x}$Ca${}_x$)RuO${}_3$
• Chromium at High Pressures: Weak Coupling and Strong Fluctuations in an Itinerant Antiferromagnet

Cited by in corpus (38)

• Enhanced superconductivity in atomically thin TaS2
• Unusual competition of superconductivity and charge-density-wave state in a compressed topological kagome metal
• A quantum phase transition from triangular to stripe charge order in NbSe${}_2$
• Strong enhancement of superconductivity at high pressures within the charge-density-wave states of 2H-TaS 2 and 2H-TaSe 2
• Disorder induced multifractal superconductivity in monolayer niobium dichalcogenides
• Strong anharmonicity induces quantum melting of charge density wave in 2H-NbSe$\_2$ under pressure
• Using controlled disorder to probe the interplay between charge order and superconductivity in NbSe2
• Revealing the competition between charge-density wave and superconductivity in CsV${}_3$Sb${}_5$ through uniaxial strain
• Nature and Raman signatures of the Higgs amplitude mode in the coexisting superconducting and charge-density-wave state
• Atomic-Scale Strain Manipulation of a Charge Density Wave
• Pressure dependence of superconducting critical temperature and upper critical field of 2H-NbS2
• Higgs-mode radiance and charge-density-wave order in 2H-NbSe${}_2$
• Superconducting dome in MoS2 and TiSe2 generated by quasiparticle-phonon coupling
• Simulating the Shastry-Sutherland Ising Model using Quantum Annealing
• Nodeless Superconductivity and its Evolution with Pressure in the Layered Dirac Semimetal 2M-WS_2
• Magnetic Pitch as a Tuning Fork for Superconductivity
• Scanning tunneling spectroscopy of layers of superconducting 2H-TaSe${}_{\text{2}}$: Evidence for a zero bias anomaly in single layers
• Soft-phonon and charge-density-wave formation in nematic BaNi${}_2$As${}_2$
• Multiple charge density wave transitions in Lu_{2} Ir_{3} Si_{5} single crystal
• Evidence of a structural quantum critical point in (Ca${}_x$Sr${}_{1-x}$)${}_3$Rh${}_4$Sn${}_{13}$ from a lattice dynamics study
• Absence of superconducting dome at the charge-density-wave quantum phase transition in 2H-NbSe2
• Lattice fluctuations, not excitonic correlations, mediated electronic localization in TiSe${}_2$
• Multipole-fluctuation pairing mechanism of $d_{x^2-y^2}+ig$ superconductivity in Sr${}_2$RuO${}_4$
• Superconducting energy gap of $2H$-NbSe${}_2$ in phonon spectroscopy
• Unveiling charge density wave quantum phase transitions by x-ray diffraction
• Incommensurate $2k_F$ density wave quantum criticality in two dimensional metals
• Possible quantum fluctuations in the vicinity of the quantum critical point of $(\mathbf{Sr},\mathbf{Ca}{)}_3\mathbf{I}{\mathbf{r}}_4\mathbf{S}{\mathbf{n}}_{13}$ revealed by high-energy X-ray diffraction study
• Nonequilibrium dynamics of spontaneous symmetry breaking into a hidden state of charge-density wave
• Magnetic order, disorder, and excitations under pressure in the Mott insulator Sr${}_2$IrO${}_4$
• The structure of the superconducting high-pressure phase of Sc${}_3$CoC${}_4$
• Magnetoelastic coupling and charge correlation lengths in a twin domain of Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ ($x=0.047$): A high-resolution X-ray diffraction study
• The maximal superconductivity in proximity to charge density wave quantum critical point in Cu${}_x$TiSe${}_2$
• Umklapp-driven first-order transition into a charge-density wave phase
• Pressure-Induced Enhancement of Superfluid Density in Transition Metal Dichalcogenides with and without Charge Density Wave
• Linear Scaling of the Superfluid Density with the Critical Temperature in the Layered Superconductor 2H-NbSe_2
• Pressure-induced enhancement of the superconducting transition temperature in La2O2Bi3AgS6
• Periodic surface modulation of $(LaSe{)}_{1.14}(NbS{e}_2)$ observed by scanning tunneling microscopy
• Superconducting Order from Disorder in 2H-TaSe${}_{2-x}$S${}_x$ (0$\le$x$\le$2)