UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Mott transition and collective charge pinning in electron doped Sr2IrO4

Wang, K; Bachar, N; Teyssier, J; Luo, W; Rischau, CW; Scheerer, G; de la Torre, A; ... van der Marel, D; + view all (2018) Mott transition and collective charge pinning in electron doped Sr2IrO4. Physical Review B , 98 (4) , Article 045107. 10.1103/PhysRevB.98.045107. Green open access

[img]
Preview
Text
PhysRevB.98.045107.pdf - ["content_typename_Published version" not defined]

Download (1MB) | Preview

Abstract

We studied the in-plane dynamic and static charge conductivity of electron doped Sr2IrO4 using optical spectroscopy and DC transport measurements. The optical conductivity indicates that the pristine material is an indirect semiconductor with a direct Mott gap of 0.55 eV. Upon substitution of 2% La per formula unit the Mott gap is suppressed except in a small fraction of the material (15%) where the gap survives, and overall the material remains insulating. Instead of a zero energy mode (or Drude peak) we observe a soft collective mode (SCM) with a broad maximum at 40 meV. Doping to 10% increases the strength of the SCM, and a zero-energy mode occurs together with metallic DC conductivity. Further increase of the La substitution doesn’t change the spectral weight integral up to 3 eV. It does however result in a transfer of the SCM spectral weight to the zero-energy mode, with a corresponding reduction of the DC resistivity for all temperatures from 4 to 300 K. The presence of a zero-energy mode signals that at least part of the Fermi surface remains ungapped at low temperatures, whereas the SCM appears to be caused by pinning a collective frozen state involving part of the doped electrons.

Type: Article
Title: Mott transition and collective charge pinning in electron doped Sr2IrO4
Open access status: An open access version is available from UCL Discovery
DOI: 10.1103/PhysRevB.98.045107
Publisher version: http://dx.doi.org/10.1103/PhysRevB.98.045107
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions
Keywords: Science & Technology, Physical Sciences, Physics, Condensed Matter, Physics, TEMPERATURE SUPERCONDUCTIVITY, EXCITATIONS, PSEUDOGAP, PHONONS, METALS, LIQUID, PHASE, BAND
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology
URI: http://discovery.ucl.ac.uk/id/eprint/10053181
Downloads since deposit
58Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item