Integrated Management of Power Aware Computation and Communication (IMPACCT)

Abstract

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Analysis of the phonon spectrum in the titanium oxyhalide TiOBr

“…The magnetic susceptibility χ(T ) [9] displays a broad maximum at high temperatures for both TiOX compounds. At T C1 ∼ 67 K and T C2 ∼ 92 K a sharp drop and a kink are observed in TiOCl.…”

“…The temperature dependence of the fit parameters [12] (ω 0 j , j , ω pj ) is shown in figures 6 and 7 for both polarizations as a percentage variation with respect to the 300 K data (e.g., ω 0 j (T )/ω 0 j (300 K), with ω 0 j (T ) = ω 0 j (T )−ω 0 j (300 K)). The two critical temperatures of the spin system, measured by χ(T ) [9,14], have been traced out with a dotted vertical line. The overall temperature dependence of the fit parameters develops in a broad temperature interval below 150 K, and tends to saturate below 30 K. The fact that this temperature interval extends well above T C1 underlines the presence of an extended fluctuation regime.…”

“…As quantum magnetism with spin- 1 2 is characterized by strong fluctuations and suppression of long range magnetic order [1] other ground states with exceptional properties may be realized. Besides Cu 2+ in the 3d 9 configuration with a hole in the e g orbitals, S = 1 2 quantum magnets are achieved with Ti 3+ and V 4+ , namely in the 3d 1 configuration and with one single d electron occupying a t 2g orbital. In addition, the smaller Jahn-Teller coupling of t 2g with respect to e g orbitals allows in certain cases an additional dynamics of these orbital states.…”