Charge-Orbital Density Wave and Superconductivity in the Strong Spin-Orbit CoupledIrTe2∶Pd

Abstract

Using transmission electron microscopy, the anomalies in resistivity and magnetic susceptibility at ~262 K in IrTe2 are found to accompany the superlattice peaks with q[over q=(1/5,0,-1/5). The wave vector is consistent with our theoretical calculation for the Fermi surface nesting vector, indicating that the ~262 K transition is of the charge-orbital density wave (DW) type. We also discovered that both Pd intercalation and substitution induce bulk superconductivity with T(c) up to ~3 K, which competes with DW in a quantum critical pointlike manner.

Charge-ordering cascade with spin–orbit Mott dimer states in metallic iridium ditelluride

“…The results offer a novel electronic paradigm, in which localized charge-ordered states interact with conduction electrons introduced by the large SOC and the interplay between SOC and Coulomb interaction plays essential roles. Pd or Pt doping, introducing additional electrons, suppresses the charge order and the system becomes a superconductor at LT [11][12][13] . It indicates that the superconducting order competes with the charge order, similarly as in the cuprates 1-3 although the mechanism can be different, and suggests a possibility for realization of superconductivity involving the spin-orbit Mott state.…”

“…The short bond length is considered as formation of Te 2 3 À polymeric bonds 17 . The band calculations predict a three dimension-like Fermi surface with a nesting instability near q ¼ (1/5 0 1/5) and Ir 3 þ and Te 1.5 À valences in the high temperature (HT) phase 11 .…”

“…Further, if the localized Mott state interacts with itinerant conduction electrons, the system possibly experiences valence fluctuations as in the 4f rare-earth materials 10 and exhibits unprecedented physical phenomena. IrTe 2 was reported as a new CDW material with a modulation vector q ¼ (1/5 0 1/5) below a CDW transition temperature T C B260 K and also as a mother compound of Ir based superconductors [11][12][13] . Various efforts have been conducted to elucidate electronic mechanisms of the charge modulation 11,13,14 , but the CDW like nature was disputable.…”

“…IrTe 2 was reported as a new CDW material with a modulation vector q ¼ (1/5 0 1/5) below a CDW transition temperature T C B260 K and also as a mother compound of Ir based superconductors [11][12][13] . Various efforts have been conducted to elucidate electronic mechanisms of the charge modulation 11,13,14 , but the CDW like nature was disputable. A recent X-ray diffraction (XRD) study suggested charge modulations not only in the Te site but also in the Ir site with dimerization below T C 15 , suggesting a possibility of the Ir site CO.…”

Electronic Structure Reconstruction by Orbital Symmetry Breaking in IrTe2

“…[1][2][3][4] Also the multi-band structure of the Fe 3d orbitals play important roles in superconductivity and magnetism of Fe pnictides and chalcogenides such as LaFeAsO 1Àx F x . 5) Recently, Pyon et al 6) and Yang et al 7) have discovered interesting interplay between lattice distortion and superconductivity in triangular lattice IrTe 2 in which multi-band Fermi surfaces are expected to play significant roles. Since the large spinorbit interaction of Ir 5d electrons is expected to entangle the spin and orbital degrees of freedom in IrTe 2 and the derived superconductors, Yang et al pointed out that the IrTe 2 system provides a new playground to explore and/or realize topological quantum states, which are currently attracting great interest in physics community.…”