اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدElectronic Structure Reconstruction across the Antiferromagnetic Transition in TaFe$_{1.23}$Te$_3$ Spin Ladder
137
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
With angle-resolved photoemission spectroscopy, we studied the electronic structure of TaFe$_{1.23}$Te$_3$, which is a two-leg spin ladder compound with a novel antiferromagnetic ground state. Quasi-two-dimensional Fermi surface is observed, indicating sizable inter-ladder hopping, which would facilitate the in-plane ferromagnetic ordering through double exchange interactions. Moreover, an energy gap is not observed at the Fermi surface in the antiferromagnetic state. Instead, the shifts of various bands have been observed. Combining these observations with density-functional-theory calculations, we propose that the large scale reconstruction of the electronic structure, caused by the interactions between the coexisting itinerant electrons and local moments, is most likely the driving force behind the magnetic transition. TaFe$_{1.23}$Te$_3$ thus provides a simpler system that contains similar ingredients as the parent compounds of iron-based superconductors, which yet could be readily modeled and understood.
قيم البحث
اقرأ أيضاً
Inelastic-neutron-scattering measurements were performed on a single crystal of the heavy-fermion paramagnet UTe$_2$ above its superconducting temperature. We confirm the presence of antiferromagnetic fluctuations with the incommensurate wavevector $
mathbf{k}_1=(0,0.57,0)$. A quasielastic signal is found, whose momentum-transfer dependence is compatible with fluctuations of magnetic moments $muparallelmathbf{a}$, with a sine-wave modulation of wavevector $mathbf{k}_1$ and in-phase moments on the nearest U atoms. Low dimensionality of the magnetic fluctuations, consequence of the ladder structure, is indicated by weak correlations along the direction $mathbf{c}$. These fluctuations saturate below the temperature $T_1^*simeq15$~K, in possible relation with anomalies observed in thermodynamic, electrical-transport and nuclear-magnetic-resonance measurements. The absence or weakness of ferromagnetic fluctuations, in our data collected at temperatures down to 2.1 K and energy transfers from 0.6 to 7.5 meV, is emphasized. These results constitute constraints for models of magnetically-mediated superconductivity in UTe$_2$.
In the nested limit of the spin-fermion model for the cuprates, one-dimensional physics in the form of half-filled two-leg ladders emerges. We show that the renormalization group flow of the corresponding ladder is towards the d-Mott phase, a gapped
spin-liquid with short-ranged d-wave pairing correlations, and reveals an intermediate SO(5)$times$SO(3) symmetry. We use the results of the renormalization group in combination with a memory-function approach to calculate the optical conductivity of the spin-fermion model in the high-frequency regime, where processes within the hot spot region dominate the transport. We argue that umklapp processes play a major role. For finite temperatures, we determine the resistivity in the zero-frequency (dc) limit. Our results show an approximate linear temperature dependence of the resistivity and a conductivity that follows a non-universal power law. A comparison to experimental data supports our assumption that the conductivity is dominated by the antinodal contribution above the pseudogap.
Through a neutron scattering, charge transport, and magnetization study, the correlated ground state in the bilayer iridium oxide Sr$_3$Ir$_2$O$_7$ is explored. Our combined results resolve scattering consistent with a high temperature magnetic phase
that persists above 600 K, reorients at the previously defined $T_{AF}=280$ K, and coexists with an electronic ground state whose phase behavior suggests the formation of a fluctuating charge or orbital phase that freezes below $T^{*}approx70$ K. Our study provides a window into the emergence of multiple electronic order parameters near the boundary of the metal to insulator phase transition of the 5d $J_{eff}=1/2$ Mott phase.
We study the electronic structure of the ladder compounds (SrCa)CuO 14-24-41 and SrCuO 123. LDA calculations for both give similar Cu 3d-bands near the Fermi energy. The hopping parameters estimated by fitting LDA energy bands show a strong anisotrop
y between the t_perp t_par intra-ladder hopping and small inter-ladder hopping. A downfolding method shows that this anisotropy arises from the ladder structure.The conductivity perpendicular to the ladders is computed assuming incoherent tunneling giving a value close to experiment.
We investigated effects of magnetic field H on antiferromagnetic (AF) structures in CeRh_{1-x}Co_xIn_5 by performing the elastic neutron scattering measurements. By applying H along the [1,-1,0] direction, the incommensurate AF state with the propaga
tion vector of q_{h1}=(1/2,1/2,0.297) observed at H=0 is replaced by the commensurate AF state with the q_{c2} = (1/2, 1/2, 1/4) modulation above 2 T for x=0.23, while the AF states with the q_{c1}=(1/2,1/2,1/2) and q_{h2}=(1/2,1/2,0.42) modulations seen at H=0 change into a single q_{c1}-AF state above ~1.6 T for x=0.7. These results suggest the different types of AF correlation for Co concentrations of 0.23 and 0.7 in an applied magnetic field H.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
