We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Dimensional reduction at a quantum critical point.
- Authors
Sebastian, S. E.; Harrison, N.; Batista, C. D.; Balicas, L.; Jaime, M.; Sharma, P. A.; Kawashima, N.; Fisher, I. R.
- Abstract
Competition between electronic ground states near a quantum critical point (QCP)—the location of a zero-temperature phase transition driven solely by quantum-mechanical fluctuations—is expected to lead to unconventional behaviour in low-dimensional systems. New electronic phases of matter have been predicted to occur in the vicinity of a QCP by two-dimensional theories, and explanations based on these ideas have been proposed for significant unsolved problems in condensed-matter physics, such as non-Fermi-liquid behaviour and high-temperature superconductivity. But the real materials to which these ideas have been applied are usually rendered three-dimensional by a finite electronic coupling between their component layers; a two-dimensional QCP has not been experimentally observed in any bulk three-dimensional system, and mechanisms for dimensional reduction have remained the subject of theoretical conjecture. Here we show evidence that the Bose–Einstein condensate of spin triplets in the three-dimensional Mott insulator BaCuSi2O6 (refs 12–16) provides an experimentally verifiable example of dimensional reduction at a QCP. The interplay of correlations on a geometrically frustrated lattice causes the individual two-dimensional layers of spin-½ Cu2+ pairs (spin dimers) to become decoupled at the QCP, giving rise to a two-dimensional QCP characterized by linear power law scaling distinctly different from that of its three-dimensional counterpart. Thus the very notion of dimensionality can be said to acquire an ‘emergent’ nature: although the individual particles move on a three-dimensional lattice, their collective behaviour occurs in lower-dimensional space.
- Subjects
CRITICAL point (Thermodynamics); CRITICAL phenomena (Physics); PHASE transitions; HIGH temperature superconductivity; CONDENSED matter
- Publication
Nature, 2006, Vol 441, Issue 7093, p617
- ISSN
0028-0836
- Publication type
Letter
- DOI
10.1038/nature04732