Spectroscopic applications of the (p,π−) reaction

Abstract

Using the strong selectivity of the A(p,~)A + 1 reaction for population of high-spin, two-particle one-hole final states, we have located and identified several candidates for high-spin states in the sd-shell nuclei Na, Al, Si, 'P, 'OS, and 'S. The spin assignments are based on both the strong population of the states and the stretched-state signature of the analyzing power angular distributions.

Superconducting state in iron-based materials and spin-fluctuation pairing theory

“…Iron-based superconductors represent quasi-two-dimensional substances in which the square lattice of iron atoms serves as the conducting plane. As was shown by the early calculations in the density functional theory (DFT) [20][21][22] , which satisfactorily agree with the results of ARPES and quantum oscillation measurements, it is the 3d 6 24 , the Fermi surface consists of four pockets: two hole pockets near the (0, 0) point and two electron pockets in the vicinity of the (π, 0) and (0, π) points (see Fig. 1).…”

Nesting-induced large magnetoelasticity in the iron-arsenide systems

“…[9][10][11] Its importance further underlined by the fact that the AF order involves a nesting wavevector, either Q 1 = (π, 0) or Q 2 = (0, π), implying a nesting driven density wave transition from a paramagnetic metal. 12 Besides the fact that T S and T N track each other closely in the temperature-doping phase diagram, there are few other indirect evidences of MEC in the FeAs systems. (1) Ab initio calculations show that the electronphonon coupling strength in the magnetic state increases by 50% compared to the paramagnetic one.…”

Cooper pairing in the insulating valence band in iron-based superconductors

“…Fe-based superconductors have generated great interest because they have highest transition temperature next to the cuprates at ambient pressure [3][4][5][6][7][8][9][10] . Typically, a Fe-based superconductor has a complex Fermi surface consisting of both electron pockets and hole pockets [11][12][13][14][15] . In comparison with other iron pnictides, LiFeAs has a much shallower hole pocket around the center of the Brillouin zone [16][17][18] .…”