A quantum magnet we studied is the brilliantly purple material BaCuSi2O6, which was originally used as a pigment (known as Han Purple) on the Terracotta Warriors. The magnetic-field tuned condensate (BEC) of spin triplets in this material is analogous to a Bose Einstein condensate of electrons.
By applying high magnetic fields, we were able to access the BEC quantum critical point in this material, and made the surprising discovery that magnetic frustration lowers the dimensionality of the BEC quantum critical point to two-dimensional, despite the three-dimensionality of the crystal lattice.
- Geometric frustration and dimensional reduction at a quantum critical point
Physical Review Letters 98, 257201 (2007)
D. Batista, J. Schmalian, N. Kawashima, P. Sengupta, S. E. Sebastian, N. Harrison, M. Jaime, I. R. Fisher
- Dimensional reduction at a quantum critical point
Nature 441, 617 (2006)
E. Sebastian, N. Harrison, C. D. Batista, L. Balicas, M. Jaime, P. A. Sharma, N. Kawashima, I.R. Fisher