M. Sugi

4f-derived Fermi surfaces of CeRu2(Si1-xGex)2 near the quantum critical point: resonant soft-X-ray ARPES study.

Angle-resolved photoelectron spectroscopy in the Ce 3d-->4f excitation region was measured for the paramagnetic state of CeRu2Si2, CeRu2(Si0.82Ge0.18)2, and LaRu2Si2 to investigate the changes of the 4f electron Fermi surfaces around the quantum critical point. While the difference of the Fermi surfaces between CeRu2Si2 and LaRu2Si2 was experimentally confirmed, a strong 4f-electron character was observed in the band structures and the Fermi surfaces of CeRu2Si2 and CeRu2(Si0.82Ge0.18)2, consequently indicating a delocalized nature of the 4f electrons in both compounds. The absence of Fermi surface reconstruction across the critical composition suggests that SDW quantum criticality is more appropriate than local quantum criticality in CeRu2(Si1-xGex)2.

Magnetic Phase Diagram and Fermi Surface Properties of CeRu2(Si1-xGex)2

We report the magnetic, transport and de Haas–van Alphen (dHvA) effect measurements to investigate the evolutions of metamagnetic behavior and electronic structure with Ge concentration x in CeRu 2 (Si 1- x Ge x ) 2 . With decreasing x , the ground state changes from ferromagnetic state to antiferromagnetic state at x a = 0.58, then to paramagnetic state at x c = 0.065. When a magnetic field is applied parallel to the [001] direction, first order metamagnetic transition takes place in the anitferromagnetic state and it changes to metamagnetic crossover in the paramagnetic state at x c . It is also found that the metamagnetic behavior as well as the magnetic phase diagram qualitatively change at x b = 0.29. The transport and dHvA effect measurements have been performed with fields applied in the (001) plane for which no metamagnetic transition takes place. With decreasing x , the magnitudes of the residual resistivity at 0.5 K, the coefficient A of T 2 term in the temperature dependence of resistivity, the...

Spin-split fermi surfaces in CexLa1-xB6CexLa1-xB6 and PrxLa1-xB6PrxLa1-xB6

We have performed the dHvA measurements on CexLa1-xB6CexLa1-xB6 and PrxLa1-xB6PrxLa1-xB6 compounds to study spin splitting of the Fermi surfaces. In PrB66 we have found new frequency branches to confirm that the Fermi surface splits into up and down spin Fermi surfaces, whereas no spin splitting has been found for x=0.25,0.5,0.75x=0.25,0.5,0.75. We have also found several new frequency branches in CeB6CeB6. The new frequency branches imply that the Fermi surfaces of up and down spin conduction electrons are significantly different in CeB6CeB6 as well as in PrB6PrB6.

Spin-split fermi surfaces in CexLa1-xB6 and PrxLa1-xB6

We have performed the dHvA measurements on CexLa1-xB6CexLa1-xB6 and PrxLa1-xB6PrxLa1-xB6 compounds to study spin splitting of the Fermi surfaces. In PrB66 we have found new frequency branches to confirm that the Fermi surface splits into up and down spin Fermi surfaces, whereas no spin splitting has been found for x=0.25,0.5,0.75x=0.25,0.5,0.75. We have also found several new frequency branches in CeB6CeB6. The new frequency branches imply that the Fermi surfaces of up and down spin conduction electrons are significantly different in CeB6CeB6 as well as in PrB6PrB6.

Spin-split fermi surfaces in and

We have performed the dHvA measurements on CexLa1-xB6CexLa1-xB6 and PrxLa1-xB6PrxLa1-xB6 compounds to study spin splitting of the Fermi surfaces. In PrB66 we have found new frequency branches to confirm that the Fermi surface splits into up and down spin Fermi surfaces, whereas no spin splitting has been found for x=0.25,0.5,0.75x=0.25,0.5,0.75. We have also found several new frequency branches in CeB6CeB6. The new frequency branches imply that the Fermi surfaces of up and down spin conduction electrons are significantly different in CeB6CeB6 as well as in PrB6PrB6.