Quantified Degeneracy, Entropy and Metal-Insulator Transition in Complex Transition-Metal Oxides
| Autor: | Myung Joon Han, Hunpyo Lee, Siheon Ryee, Jae-Hoon Sim |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Physics
Phase transition Strongly Correlated Electrons (cond-mat.str-el) Condensed matter physics Superlattice FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Condensed Matter - Strongly Correlated Electrons Transition metal 0103 physical sciences Condensed Matter::Strongly Correlated Electrons Metal–insulator transition 010306 general physics 0210 nano-technology Entropy (order and disorder) |
| Popis: | Understanding complex correlated oxides and their phase transitions has long been a challenge. The difficulty largely arises from the intriguing interplay between multiple degrees of freedoms. While degeneracy can play an important role in determining material characteristics, there is no well-defined way to quantify and to unveil its role in real materials having complicated band structures. Here we suggest a way to quantify the `effective degeneracy' relevant to metal-insulator transition by introducing entropy-like terms. This new quantity well describes the electronic behaviors of transition-metal oxides as a function of external and internal parameters. With $3d$ titanates, $4d$ ruthenates, and $5d$ iridates as our examples, we show that this new effective quantity provides useful insights to understand these systems and their phase transitions. For LaTiO$_3$/LaAlO$_3$ superlattice, we suggest a novel `degeneracy control' metal-insulator transition. First submitted (to other journal) on 13 Jul 2017. Eventually accepted in PRB |
| Databáze: | OpenAIRE |
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