Dimensionality controlled Mott transition and correlation effects in single- and bi-layer perovskite iridates

TL;DR

This study uses ARPES to investigate the electronic structure of Sr2IrO4 and Sr3Ir2O7, revealing how dimensionality influences the Mott transition and highlighting the limitations of existing theoretical models.

Contribution

It provides direct experimental measurements of coupling parameters and Mott gaps, emphasizing the role of inter-cell coupling and correlations in these iridates.

Findings

Dimensionality controls the Mott transition in 5d TMOs.

ARPES data reveal discrepancies with LDA+U+SOC calculations.

Inter-cell coupling significantly affects the Mott gap size.

Abstract

We studied Sr2IrO4 and Sr3Ir2O7 using angle-resolved photoemission spectroscopy (ARPES), making direct experimental determinations of intra- and inter-cell coupling parameters as well as Mott correlations and gap sizes. The results are generally consistent with LDA+U+Spin-orbit coupling (SOC) calculations, though the calculations missed the momentum positions of the dominant electronic states and neglected the importance of inter-cell coupling on the size of the Mott gap. The calculations also ignore the correlation-induced spectral peak widths, which are critical for making a connection to activation energies determined from transport experiments. The data indicate a dimensionality-controlled Mott transition in these 5d transition-metal oxides (TMOs).