19 December 2016

Special phase transition in lead chromium oxide

Dielectric measurement of α-PbCrO3 at ambient pressure. Dielectric measurement of α-PbCrO3 at ambient pressure.

Controlled by electron interactions, the Mott transition is accompanied by a reduction in the volume of the atomic lattice.

What did scientists discover?

The stable, low-pressure phase of lead chromium oxide (PbCrO3) is associated with a ferroelectric distortion — a shifting of atoms that creates an electric field. Researchers have found that this distortion is suppressed at high pressure, leading to a so-called Mott phase transition — a transition from a metal to an insulator that arises from interactions between electrons.

Why is this important?

The studies show clearly the existence of an electron-interaction-controlled Mott transition that is accompanied by a reduction in the volume of the atomic lattice.


This research was conducted at the MagLab's High B/T Facility located at the University of Florida.

When the atoms move closer together as pressure is applied, the strength of interactions between electrons is changed. In more technical terms, a volume collapse results in greater screening of the Coulomb interaction, driving a Mott transition without any symmetry breaking in the crystalline lattice. This is highly unusual — and perhaps unique — to PbCrO3.

Who did the research?

S. Wang1,2,3, J. Zhu2,3,4, X. Yu3,4, J. Zhang3, W. Wang1, L. Bai2,5, J. Qian6, Y. Zhao2,3, A. Serafin7, L. Yin7, J.-S. Xia7, C. Jin4,8, D. He1

1Sichuan University; 2University of Nevada; 3Los Alamos National Laboratory; 4National Laboratory for Condensed Matter Physics, Beijing; 5Carnegie Institution of Washington; 6US Synthetic Corporation; 7National MagLab, University of Florida; 8Center for Quantum Matter, Beijing.

Why did they need the MagLab?

These studies required the specialized capability of low temperatures, high magnetic fields and high-sensitivity dielectric susceptibility measurements of the MagLab's High B/T Facility.

Details for scientists


This research was funded by the following grants: G.S. Boebinger (NSF DMR-1157490)

For more information, contact Neil Sullivan.


  • Research Area: Condensed Matter Technique Development, Magnetism and Magnetic Materials
  • Research Initiatives: Materials
  • Facility / Program: High B/T
  • Year: 2016
Last modified on 19 December 2016