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Quantum critical state in a magnetic quasicrystal
Kazuhiko Deguchi1, Shuya Matsukawa, Noriaki K Sato
1Department of Physics, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan. deguchi@edu3.phys.nagoya-u.ac.jp
Nature Materials
|October 9, 2012
Summary
Researchers observed quantum critical phenomena in quasicrystals, revealing unique electronic states. This quantum criticality, linked to aperiodic structures, is robust against pressure, unlike in crystalline phases.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Quantum Materials
Background:
- Quasicrystals exhibit long-range, aperiodic atomic structures with unique symmetries.
- The electronic states in quasicrystals (extended vs. localized) remain a key unresolved question.
- Understanding electronic properties is crucial for unlocking quasicrystal potential.
Purpose of the Study:
- To investigate the electronic states and quantum phenomena in quasicrystals.
- To determine if quantum criticality is present in quasicrystals.
- To compare quasicrystal electronic states with those of crystalline approximants.
Main Methods:
- Experimental observation of quantum (T=0) critical phenomena in an Au-Al-Yb quasicrystal.
- Measurement of magnetic susceptibility and electronic specific heat coefficient.
- Application of hydrostatic pressure to assess phenomenon robustness.
Main Results:
- Observed divergence in magnetic susceptibility and electronic specific heat coefficient as temperature approaches zero (T→0).
- Demonstrated that this quantum critical phenomenon is robust under hydrostatic pressure.
- Found no such divergence in a comparable crystalline approximant phase.
Conclusions:
- The quantum criticality is intrinsically linked to the unique electronic state of quasicrystals.
- This state can be described as a spatially confined critical state.
- Suggests a potential general law governing both conventional crystals and quasicrystals.
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