Electron Transport Properties of UAsSe

Observation of a kink in the dispersion of f-electrons

“…Uranium dipnictides UX 2 (X = P, As, Sb and Bi) are a family of correlated f -electron antiferromagnets with tetragonal structure (P 4/nmm) which have relatively high Néel temperatures [11,12] and complex transport properties [13]. The electronic specific heat of USb 2 of 25 mJ K −2 mol −1 is small in comparison with Ce-based heavy fermions, but is typical for many uranium compounds where strong hybridization between 5f and conduction electrons leads to itinerant behavior.…”

Microscopic mechanism for the unusual antiferromagnetic order and the pressure-induced transition to ferromagnetism in USb2

“…In the present work, motivated by these findings, we develop a low-energy microscopic model rationalizing the unusual antiferromagnetism 15,19 and the pressureinduced transition to ferromagnetism 21 in USb 2 . Re-lying on the obtained results we also address properties of magnetic states observed in other U-based compounds: isostructural to USb 2 UAs 2 and UBi 2 16,17,22,23 , UAsSe [24][25][26] and URh x Ir 1−x Ge 27 . Moreover, we provide arguments that ferromagnetism in pressurized USb 2 has the same character as ferromagnetism [28][29][30] in the famous spin-triplet superconductor UGe 2 31 .…”

“…It must be noted however that a present theoretical approach is not wellsuited to address UAsSe for its complete set of properties. Namely, the Kondo-signatures 24,25 cannot be addressed within renormalized mean-field theory which treats quantum fluctuations in an oversimplified manner to account properly for this class of many-body effects.…”

Valence instability across the magnetostructural transition in USb2

“…We also point out that the same manuscripts no longer include the f 1 state in their analysis (only f i , i=2, 3,4,5,6) and the reason is not clear. At least in the case of USb 2 , it is expected that the f 1 , f 2 , and f 3 states contribute to the total electronic state in this system.…”

“…[5] The antiferromagnetic ordering temperature (T N ) decreases with increasing atomic size (and thus U-U spacing) in contrast to the Hill scenario for U-compounds, and shows ordering temperatures of T N =273 K, 203 K, and 183 K for UAs 2 , USb 2 , and UBi 2 , respectively. [3,6,7] Owing to its distinct crystal structure, UP 2 does not follow this trend, and shows an ordering temperatures of 203 K, though doping studies in the U(P,As) 2 system have shown a steady increase in T N as the As content is increased. [8] Pressure-dependent transport measurements performed on USb 2 indicate that T N approaches that of UAs 2 , but an abrupt AFM-FM transition occurs near P=8 GPa, reducing the ordering temperature by over 100 K. [9] The AFM-FM transition has been the subject of several recent theoretical calculations, though from an experimental standpoint, only little is known about this transition.…”