Spectral weight suppression near a metal-insulator transition in a double-layer electron-doped iridate

Abstract

The perovskite iridates Sr 2 IrO 4 and Sr 3 Ir 2 O 7 represent novel systems for exploring the electronic structure that is characteristic of Mott insulators upon carrier doping. Using angle-resolved photoemission spectroscopy (ARPES), we reveal a previously unobserved suppression of spectral weight near the Fermi level in the conduction band of very lightly electron-doped (Sr 1−x La x) 3 Ir 2 O 7 followed by a loss of coherence at high temperature. The doping and temperature dependence of this suppression suggests a correspondence with the antiferromagnetic Mott state. These results connect (Sr 1−x La x) 3 Ir 2 O 7 to other doped Mott insulators and add to the growing evidence of universal physics in these systems.

Putative magnetic quantum criticality in (Sr1−xLax)3Ir2O7Vale1, Hunter2 2018Phys. Rev. B1000View full textAdd to dashboardCite

“…The REXS results also show a possible crossover between quantum paramagnetic and quantum critical phe- [12,13] T 2 [12,13] T N [12] T s [12] T cr [18] T coh [17] T DW [14] IMT nomenology somewhere between 100 and 200 K. This is consistent with our value of T * , which implies that the Hertz-Millis-Moriya picture (Fig. 2d) may be relevant for (Sr 1−x La x ) 3 Ir 2 O 7 .…”

“…Neutron scattering and second harmonic generation (SHG) measurements determined that the IMT is first order, with a structural phase transition occurring in the metallic phase at T s ≈ 200 K. 12,14 Yet no pseudogap could be observed by angle-resolved photoelectron spectroscopy (ARPES), with small electron-like Fermi pockets present in the metallic phase. [15][16][17] Furthermore, electronic phase separation does occur in the vicinity of the IMT, but disappears for x > 0.04. 12 Magnetization and neutron scattering measurements show that Néel LRO disappears above the IMT.…”

“…A further change in slope occurs around 100 K, which coincides remarkably well with the loss of coherent quasiparticle spectral weight at T coh observed via ARPES. 17 Between these two temperatures, dρ/dT is approximately constant, implying ρ ∝ T . Such behavior is expected for good metals well above the Debye temperature Θ D due to electron-phonon scattering.…”

Doping-dependent correlation effects in (Sr1−xLax)3Ir2O7Affeldt1, Hogan2, Denlinger3 et al. 2018Phys. Rev. BSelf Cite3022View full textAdd to dashboardCite

“…Much recent progress has been made in understanding the nature of the spin-orbit Mott state in the layered perovskite iridates 2,3,6,[12][13][14][16][17][18]24,[27][28][29]32,36 , in which spin-orbit coupling and Coulomb electron-electron correlations combine to form an insulating state. The spinorbit coupling arranges the t 2g bands by an effective angular momentum into a filled J eff = 3 2 state and a half-filled J eff = 1 2 state. The Coulomb correlation is sufficient to localize the J eff = 1 2 electrons in a Mott state, with Mott-like gaps observed in both the single-layer Sr 2 IrO 4 13 and the the bilayer Sr 3 Ir 2 O 7 24,32 .…”

Formation of Sn‐Induced Nanowires on Si(557)

“…The targeted manipulation of Mott‐systems arouse a lot of interest. For instance, doping leads to various phases like high‐temperature superconductivity, charge‐transfer insulators, or robust metallic states . For α ‐Sn on Si(111) a metallic quasi‐particle state was found within the Mott gap, if the system is modified by means of the acceptor concentration of the Si substrate .…”