Nesting-driven multipolar order in CeB6 from photoemission tomography

Abstract

Some heavy fermion materials show so-called hidden-order phases which are invisible to many characterization techniques and whose microscopic origin remained controversial for decades. Among such hidden-order compounds, CeB6 is of model character due to its simple electronic configuration and crystal structure. Apart from more conventional antiferromagnetism, it shows an elusive phase at low temperatures, which is commonly associated with multipolar order. Here we show that this phase roots in a Fermi surface instability. This conclusion is based on a full 3D tomographic sampling of the electronic structure by angle-resolved photoemission and comparison with inelastic neutron scattering data. The hidden order is mediated by itinerant electrons. Our measurements will serve as a paradigm for the investigation of hidden-order phases in f-electron systems, but also generally for situations where the itinerant electrons drive orbital or spin order.

Doping-induced redistribution of magnetic spectral weight in the substituted hexaborides Ce1−xLaxB6 and Nikitin1, Portnichenko2, Dukhnenko3 et al. 2018Phys. Rev. BSelf Cite123160View full textAdd to dashboardCite

“…Previously we already argued that the propagation vectors of both AFM and AFQ phases in pure CeB 6 are dictated by the nesting properties of its Fermi surface [8]. In nonmagnetic LaB 6 and antiferromagnetic NdB 6 , dHvA measurements found no significant difference in the size of the Fermi surface due to a strong localization of the Nd 3+ 4 f electrons [70,71].…”

“…Knowing that both La and Nd substitutions lead to an effective hole doping and should therefore cause similar changes of the Fermi surface, it is natural to expect a strong rise of intensity at the X point with simultaneous suppression of excitations at the Γ and R points also in Ce 1−x Nd x B 6 . At high Nd concentrations, the peak at the X point would represent critical paramagnon fluctuations of phase VI above T N , whereas on the La-rich side of the phase diagram similar fluctuations are also present, but never condense into a long-range magnetically ordered phase because of the strong dilution of the moments [8]. We are therefore interested in looking at an intermediate Nd concentration, shortly before reaching the phase VI, to see if the spectral-weight transfer to the X point takes place in a similar fashion as on the La-doped side.…”

“…This limits its applicability to materials with highly 3-dimensional (3D) band structures. Extraction of Fermisurface nesting vectors from ARPES data is possible and has been successful in many earlier works [1][2][3][4][5][6][7][8], but it usually relies on a technically demanding fit of the whole low-energy band structure to a tight-binding model with a consequent momentum integration to extract the peaks in a two-particle correlation function. This method is, therefore, indirect.…”

“…* Corresponding author: Dmytro.Inosov@tu-dresden. de A handful of earlier works on magnetic heavy-fermion metals, where conduction electrons are involved in the formation of magnetic order, suggest that the low-energy dynamic spin susceptibility χ(ω, Q), measured with diffuse neutron scattering, provides direct information about the nesting vectors [7][8][9][10][11][12][13][14][15][16]. Due to the bulk sensitivity of neutron scattering, it therefore serves as a complementary method for probing the 3D electronic structure.…”

“…In a recent work [8], some of us have investigated electronic structure of pure CeB 6 using both ARPES and inelastic neutron scattering (INS). We observed strong spectral intensity at the points, which correspond to the propagation vectors of the AFQ and AFM phases, and additional intensity maxima at the Γ and X points.…”