Order parameter fluctuations at a buried quantum critical point.


Journal Article

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.

Full Text

Duke Authors

Cited Authors

  • Feng, Y; Wang, J; Jaramillo, R; van Wezel, J; Haravifard, S; Srajer, G; Liu, Y; Xu, Z-A; Littlewood, PB; Rosenbaum, TF

Published Date

  • May 2012

Published In

Volume / Issue

  • 109 / 19

Start / End Page

  • 7224 - 7229

PubMed ID

  • 22529348

Pubmed Central ID

  • 22529348

Electronic International Standard Serial Number (EISSN)

  • 1091-6490

International Standard Serial Number (ISSN)

  • 0027-8424

Digital Object Identifier (DOI)

  • 10.1073/pnas.1202434109


  • eng