Emergence of topological Mott insulators in proximity of quadratic band touching points

• Видавець: Інститут фізики конденсованих систем НАН України
• Дата: 2019
• Автори: Mandal, I., Gemsheim, S.
• Формат: Стаття
• Мова: English
• Опубліковано: Інститут фізики конденсованих систем НАН України 2019
• Назва видання: Condensed Matter Physics
• Онлайн доступ: http://dspace.nbuv.gov.ua/handle/123456789/157475
• Цитувати: Emergence of topological Mott insulators in proximity of quadratic band touching points / I. Mandal, S. Gemsheim // Condensed Matter Physics. — 2019. — Т. 22, № 1. — С. 13701: 1–10. — Бібліогр.: 13 назв. — англ.

Recently, the field of strongly correlated electrons has begun an intense search for a correlation induced topological insulating phase. An example is the quadratic band touching point which arises in a checkerboard lattice at half-filling, and in the presence of interactions gives rise to topological Mott insulators. In this work, we perform a mean-field theory computation to show that such a system shows instability to topological insulating phases even away from half-filling (chemical potential µ = 0). The interaction parameters consist of on-site repulsion (U), nearest-neighbour repulsion (V), and a next-nearest-neighbour correlated hopping (tc). The tc interaction originates from strong Coulomb repulsion. By tuning the values of these parameters, we obtain a desired topological phase that spans the area around (V = 0, µ = 0), extending to regions with (V > 0, µ = 0) and (V > 0, µ > 0). This extends the realm of current experimental efforts to find these topological phases.