Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements
High temperature superconductivity has been found in many kinds of compounds built from planes of Cu and O, separated by spacer layers. Understanding why critical temperatures are so high has been the subject of numerous investigations and extensive controversy. To realize high temperature supercond...
| Main Authors: | , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
American Physical Society
2018-05-01
|
| Series: | Physical Review X |
| Online Access: | http://doi.org/10.1103/PhysRevX.8.021038 |
| _version_ | 1828954133265121280 |
|---|---|
| author | Swagata Acharya Cédric Weber Evgeny Plekhanov Dimitar Pashov A. Taraphder Mark Van Schilfgaarde |
| author_facet | Swagata Acharya Cédric Weber Evgeny Plekhanov Dimitar Pashov A. Taraphder Mark Van Schilfgaarde |
| author_sort | Swagata Acharya |
| collection | DOAJ |
| description | High temperature superconductivity has been found in many kinds of compounds built from planes of Cu and O, separated by spacer layers. Understanding why critical temperatures are so high has been the subject of numerous investigations and extensive controversy. To realize high temperature superconductivity, parent compounds are either hole doped, such as La_{2}CuO_{4} (LCO) with Sr (LSCO), or electron doped, such as Nd_{2}CuO_{4} (NCO) with Ce (NCCO). In the electron-doped cuprates, the antiferromagnetic phase is much more robust than the superconducting phase. However, it was recently found that the reduction of residual out-of-plane apical oxygen dramatically affects the phase diagram, driving those compounds to a superconducting phase. Here we use a recently developed first-principles method to explore how displacement of the apical oxygen (AO) in LCO affects the optical gap, spin and charge susceptibilities, and superconducting order parameter. By combining quasiparticle self-consistent GW (QS GW) and dynamical mean-field theory (DMFT), we show that LCO is a Mott insulator, but small displacements of the apical oxygen drive the compound to a metallic state through a localization-delocalization transition, with a concomitant maximum in d-wave order parameter at the transition. We address the question of whether NCO can be seen as the limit of LCO with large apical displacements, and we elucidate the deep physical reasons why the behavior of NCO is so different from the hole-doped materials. We shed new light on the recent correlation observed between T_{c} and the charge transfer gap, while also providing a guide towards the design of optimized high-T_{c} superconductors. Further, our results suggest that strong correlation, enough to induce a Mott gap, may not be a prerequisite for high-T_{c} superconductivity. |
| first_indexed | 2024-12-14T07:23:53Z |
| format | Article |
| id | doaj.art-338d42305fd148fab85236a078474030 |
| institution | Directory Open Access Journal |
| issn | 2160-3308 |
| language | English |
| last_indexed | 2024-12-14T07:23:53Z |
| publishDate | 2018-05-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review X |
| spelling | doaj.art-338d42305fd148fab85236a0784740302022-12-21T23:11:33ZengAmerican Physical SocietyPhysical Review X2160-33082018-05-018202103810.1103/PhysRevX.8.021038Metal-Insulator Transition in Copper Oxides Induced by Apex DisplacementsSwagata AcharyaCédric WeberEvgeny PlekhanovDimitar PashovA. TaraphderMark Van SchilfgaardeHigh temperature superconductivity has been found in many kinds of compounds built from planes of Cu and O, separated by spacer layers. Understanding why critical temperatures are so high has been the subject of numerous investigations and extensive controversy. To realize high temperature superconductivity, parent compounds are either hole doped, such as La_{2}CuO_{4} (LCO) with Sr (LSCO), or electron doped, such as Nd_{2}CuO_{4} (NCO) with Ce (NCCO). In the electron-doped cuprates, the antiferromagnetic phase is much more robust than the superconducting phase. However, it was recently found that the reduction of residual out-of-plane apical oxygen dramatically affects the phase diagram, driving those compounds to a superconducting phase. Here we use a recently developed first-principles method to explore how displacement of the apical oxygen (AO) in LCO affects the optical gap, spin and charge susceptibilities, and superconducting order parameter. By combining quasiparticle self-consistent GW (QS GW) and dynamical mean-field theory (DMFT), we show that LCO is a Mott insulator, but small displacements of the apical oxygen drive the compound to a metallic state through a localization-delocalization transition, with a concomitant maximum in d-wave order parameter at the transition. We address the question of whether NCO can be seen as the limit of LCO with large apical displacements, and we elucidate the deep physical reasons why the behavior of NCO is so different from the hole-doped materials. We shed new light on the recent correlation observed between T_{c} and the charge transfer gap, while also providing a guide towards the design of optimized high-T_{c} superconductors. Further, our results suggest that strong correlation, enough to induce a Mott gap, may not be a prerequisite for high-T_{c} superconductivity.http://doi.org/10.1103/PhysRevX.8.021038 |
| spellingShingle | Swagata Acharya Cédric Weber Evgeny Plekhanov Dimitar Pashov A. Taraphder Mark Van Schilfgaarde Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements Physical Review X |
| title | Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements |
| title_full | Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements |
| title_fullStr | Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements |
| title_full_unstemmed | Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements |
| title_short | Metal-Insulator Transition in Copper Oxides Induced by Apex Displacements |
| title_sort | metal insulator transition in copper oxides induced by apex displacements |
| url | http://doi.org/10.1103/PhysRevX.8.021038 |
| work_keys_str_mv | AT swagataacharya metalinsulatortransitionincopperoxidesinducedbyapexdisplacements AT cedricweber metalinsulatortransitionincopperoxidesinducedbyapexdisplacements AT evgenyplekhanov metalinsulatortransitionincopperoxidesinducedbyapexdisplacements AT dimitarpashov metalinsulatortransitionincopperoxidesinducedbyapexdisplacements AT ataraphder metalinsulatortransitionincopperoxidesinducedbyapexdisplacements AT markvanschilfgaarde metalinsulatortransitionincopperoxidesinducedbyapexdisplacements |