Predicting excessive temperature Bose-Einstein condensation of excitons

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Predicting high temperature Bose-Einstein condensation of excitons
Cost switch excitons in organic-2D heterostructure: Schematic determine exhibiting charge-transfer excitons within the ZnPc-MoS2 organic-2D heterostructure. The bottom vitality cost switch excitons in ZnPc/MoS2 heterostucture are predicted to bear Bose-Einstein condensation at round 50 Okay to 100 Okay. Credit score: Nationwide College of Singapore

Nationwide College of Singapore researchers have predicted that an unique state of matter often known as a Bose-Einstein condensate can exist at comparatively excessive temperatures (round 50 Okay to 100 Okay) in methods comprising natural molecules on two-dimensional (2D) semiconducting supplies.

A Bose-Einstein condensate is a state of matter through which all particles have the identical vitality and are fully coordinated. From a bodily viewpoint, these particles clump collectively and begin to behave as if they’re a part of a single bigger particle. The 2001 Nobel Prize in Physics was awarded for the conclusion of Bose-Einstein condensation. This phenomenal breakthrough was first achieved in a set of rubidium atoms at an ultra-low temperature of 20 nK. This management of the state of matter is predicted to result in technological breakthroughs, and in addition allows the conclusion of superfluidity.

On this work, Prof Quek Su Ying from the Division of Physics, Nationwide College of Singapore, and her postdoctoral fellow, Dr. Ulman Kanchan, predicted that Bose-Einstein condensation (BEC) can happen at round 50 Okay to 100 Okay in natural 2D materials methods (see Determine) via their computation. This BEC temperature is orders of magnitude larger than that beforehand achieved utilizing atoms. The particles that condense within the organic-2D materials methods are certain electron-hole pairs (excitons) which might be induced within the system via irradiation with gentle. The electron resides within the 2D semiconductor (molybdenum disulphide, MoS2) and the outlet within the natural molecule (zinc phthalocyanine, ZnPc), in what is named a “cost switch exciton.” The spatial separation between the electron and gap, along with the strongly certain nature of the excitons in these low dimensional supplies, ends in lengthy exciton lifetimes, that are important for BEC to happen. Crucially, the anticipated BEC temperature is far larger than that in atoms. It is because the BEC temperature is inversely proportional to the particle mass, and the mass is far smaller than typical atomic plenty.

Previous to this prediction, BEC of cost switch excitons was noticed at round 100 Okay in bilayers of 2D supplies. Nevertheless, one sensible problem within the realization of BEC in these methods was the necessity for cautious alignment of the 2 layers of fabric. Misaligned bilayers host excitons with giant momentum, which hinder the formation of the condensate. Within the case of organic-2D materials methods, the slender bandwidth of the molecular states suggest that the cost switch excitons have very small momentum, thus favoring BEC formation.

Prof Quek mentioned, “Natural molecules similar to transition steel phthalocyanines readily type ordered, self-assembled monolayers on 2D supplies. The prediction of excessive BEC of excitons in organic-2D materials methods is predicted to result in extra sensible realizations of this unique state of matter, and paves the best way for the examine of intriguing functions associated to Bose-Einstein condensates.”


Spontaneous Bose-Einstein condensation of excitons


Extra info:
Kanchan Ulman et al, Natural-2D Materials Heterostructures: A Promising Platform for Exciton Condensation and Multiplication, Nano Letters (2021). DOI: 10.1021/acs.nanolett.1c03435

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Predicting excessive temperature Bose-Einstein condensation of excitons (2021, December 6)
retrieved 11 December 2021
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