Title: Quantum matter in your car bumper
Chromium is commonly used as a metallic layer in car bumpers and is a crucial element for stainless steel. In addition, chromium is the only element in the periodic table that displays antiferromagnetism, where the electron spins form a spin-density wave of alternating up and down spins. In this talk, I will show that despite being a common and “simple” metal, chromium displays unusual physical properties not described within the standard models of solid state physics that are usually limited to much more complex materials. It has a quantum critical point[i], and exhibits non-Fermi liquid behavior[ii]. In addition, when the film thickness is thin, the spin-density wave is quantized[iii].
[i] “Quantum phase transition in a common metal”, A. Yeh, Yeong-Ah Soh, J. Brooke, G. Aeppli, T. F. Rosenbaum, and S. M. Hayden, Nature (London) 419, 459 (2002).
[ii] “Non-Fermi liquid behavior in a simple metal”, Ravi K. Kummamuru and Yeong-Ah Soh, under review by Nature.
[iii] “Electrical effects of spin density wave quantization and magnetic domain walls
in chromium”, Ravi K. Kummamuru and Yeong-Ah Soh, Nature 452, 859 – 863
(2008).