Details

Autor(en) / Beteiligte

• Zhang, Yiming
• Hou, Bowen
• Wu, Yu
• Chen, Ying
• Xia, Yujie
• Mei, Haodong
• Kong, Mingran
• Peng, Lei
• Shao, Hezhu
• Cao, Jiang
• Liu, Wenjun
• Zhu, Heyuan
• Zhang, Hao

Titel

Towards high-temperature electron-hole condensate phases in monolayer tetrels metal halides: Ultra-long excitonic lifetimes, phase diagram and exciton dynamics

Ist Teil von

• Materials today physics, 2022-01, Vol.22, p.100604, Article 100604

Ort / Verlag

Elsevier Ltd

Erscheinungsjahr

2022

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Excitons as composite bosons have been predicted to condense into Bose Einstein Condensation (BEC), Berezinskii-Kosterlitz-Thouless (BKT) superfluid or electron-hole liquid (EHL) states. However, short lifetime and small binding energy are the main obstacles that hinder the formation and observation of excitonic condensate at high temperature. Here we demonstrate excellent two-dimensional Tetrel Metal Halides (TMHs) platforms for excitonic quantum phase transition researches. We find that excitons in those monolayers possess effective masses similar to the free electron, promising large thermal de Broglie wavelengths. They can maintain stable bosonic characteristic at high temperature and concentration up to 1012 cm−2. The calculation on PbI2, PbBr2, PbCl2, SnI2, SnBr2, SnCl2 indicates BEC transition temperatures at 49 K, 103 K, 252 K, 36 K, 78 K, 152 K, comparable to the experimentally observed exciton BEC in MoSe2–WSe2 bilayer and 1 T-TiSe2 at 100 K and 190 K respectively. Besides, we confirm that the thermal equilibrium of excitonic subsystem can be established really fast, up to ∼10–100 fs. The excitons can live for ∼1–100 μs without direct radiation, beneficial for the formation and observation of condensate state. Our result paves the way not only for studies of quantum phase transition researches, but also for high-temperature excitonic devices. •Room-temperature stable excitons in monolayer TMH materials.•Optical properties of monolayer TMH materials including exciton effect.•Prediction of the BEC and superfluid phase transitions.•Analysis of the exciton dynamic processes in monolayer TMH materials.