Bose–Einstein condensation of quasi-equilibrium magnons at room temperature under pumping

Nature ◽  
2006 ◽  
Vol 443 (7110) ◽  
pp. 430-433 ◽  
Author(s):  
S. O. Demokritov ◽  
V. E. Demidov ◽  
O. Dzyapko ◽  
G. A. Melkov ◽  
A. A. Serga ◽  
...  
Keyword(s):  
Room Temperature ◽  
Einstein Condensation ◽  
Quasi Equilibrium ◽  
Bose Einstein Condensation ◽  
Bose Einstein

Bose–Einstein condensation of spin wave quanta at room temperature

2011 ◽  
Vol 369 (1951) ◽  
pp. 3575-3587 ◽  
Author(s):  
O. Dzyapko ◽  
V. E. Demidov ◽  
G. A. Melkov ◽  
S. O. Demokritov
Keyword(s):  
Room Temperature ◽  
Chemical Potential ◽  
Spin Waves ◽  
Einstein Condensation ◽  
Quasi Equilibrium ◽  
Magnetic Media ◽  
Bose Einstein Condensation ◽  
Garnet Films ◽  
Iron Garnet ◽  
Bose Einstein

Spin waves are delocalized excitations of magnetic media that mainly determine their magnetic dynamics and thermodynamics at temperatures far below the critical one. The quantum-mechanical counterparts of spin waves are magnons, which can be considered as a gas of weakly interacting bosonic quasi-particles. Here, we discuss the room-temperature kinetics and thermodynamics of the magnon gas in yttrium iron garnet films driven by parametric microwave pumping. We show that for high enough pumping powers, the thermalization of the driven gas results in a quasi-equilibrium state described by Bose–Einstein statistics with a non-zero chemical potential. Further increases of the pumping power cause a Bose–Einstein condensation documented by an observation of the magnon accumulation at the lowest energy level. Using the sensitivity of the Brillouin light scattering spectroscopy to the degree of coherence of the scattering magnons, we confirm the spontaneous emergence of coherence of the magnons accumulated at the bottom of the spectrum, occurring if their density exceeds a critical value.

scholarly journals Evidence for spin current driven Bose-Einstein condensation of magnons

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
B. Divinskiy ◽  
H. Merbouche ◽  
V. E. Demidov ◽  
K. O. Nikolaev ◽  
L. Soumah ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Potential ◽  
Spin Current ◽  
Einstein Condensation ◽  
Electronic Control ◽  
Spintronic Devices ◽  
Bose Einstein Condensation ◽  
Magnetic Insulators ◽  
Spatially Extended ◽  
Bose Einstein

AbstractThe quanta of magnetic excitations – magnons – are known for their unique ability to undergo Bose-Einstein condensation at room temperature. This fascinating phenomenon reveals itself as a spontaneous formation of a coherent state under the influence of incoherent stimuli. Spin currents have been predicted to offer electronic control of Bose-Einstein condensates, but this phenomenon has not been experimentally evidenced up to now. Here we show that current-driven Bose-Einstein condensation can be achieved in nanometer-thick films of magnetic insulators with tailored nonlinearities and minimized magnon interactions. We demonstrate that, above a certain threshold, magnons injected by the spin current overpopulate the lowest-energy level forming a highly coherent spatially extended state. We quantify the chemical potential of the driven magnon gas and show that, at the critical current, it reaches the energy of the lowest magnon level. Our results pave the way for implementation of integrated microscopic quantum magnonic and spintronic devices.

Bose–Einstein Condensation of Exciton-Polaritons in Organic Microcavities

2020 ◽  
Vol 71 (1) ◽  
pp. 435-459 ◽  
Author(s):  
Jonathan Keeling ◽  
Stéphane Kéna-Cohen
Keyword(s):  
Room Temperature ◽  
Organic Molecules ◽  
Einstein Condensation ◽  
Electronic Excitations ◽  
Optical Mode ◽  
Optical Cavities ◽  
Bose Einstein Condensation ◽  
Exciton Polaritons ◽  
Basic Physics ◽  
Bose Einstein

Bose–Einstein condensation describes the macroscopic occupation of a single-particle mode: the condensate. This state can in principle be realized for any particles obeying Bose–Einstein statistics; this includes hybrid light-matter excitations known as polaritons. Some of the unique optoelectronic properties of organic molecules make them especially well suited for the realization of polariton condensates. Exciton-polaritons form in optical cavities when electronic excitations couple collectively to the optical mode supported by the cavity. These polaritons obey bosonic statistics at moderate densities, are stable at room temperature, and have been observed to form a condensed or lasing state. Understanding the optimal conditions for polariton condensation requires careful modeling of the complex photophysics of organic molecules. In this article, we introduce the basic physics of exciton-polaritons and condensation and review experiments demonstrating polariton condensation in molecular materials.

Exciton-polariton Bose-Einstein condensation with a polymer at room temperature

2015 ◽  
Author(s):  
Thilo Stöferle ◽  
Johannes D. Plumhof ◽  
Lijian Mai ◽  
Ullrich Scherf ◽  
Rainer F. Mahrt
Keyword(s):  
Room Temperature ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

scholarly journals Excitonic Bose-Einstein condensation inTa2NiSe5above room temperature

2014 ◽  
Vol 90 (15) ◽  
Author(s):  
K. Seki ◽  
Y. Wakisaka ◽  
T. Kaneko ◽  
T. Toriyama ◽  
T. Konishi ◽  
...  
Keyword(s):  
Room Temperature ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Bose Einstein

scholarly journals Room temperature exciton–polariton Bose–Einstein condensation in organic single-crystal microribbon cavities

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ji Tang ◽  
Jian Zhang ◽  
Yuanchao Lv ◽  
Hong Wang ◽  
Fa Feng Xu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Binding Energies ◽  
Einstein Condensation ◽  
Coherent Light ◽  
Optical Logic ◽  
Bose Einstein Condensation ◽  
Organic Single Crystal ◽  
Frenkel Excitons ◽  
Bose Einstein

AbstractExciton–polariton Bose–Einstein condensation (EP BEC) is of crucial importance for the development of coherent light sources and optical logic elements, as it creates a new state of matter with coherent nature and nonlinear behaviors. The demand for room temperature EP BEC has driven the development of organic polaritons because of the large binding energies of Frenkel excitons in organic materials. However, the reliance on external high-finesse microcavities for organic EP BEC results in poor compactness and integrability of devices, which restricts their practical applications in on-chip integration. Here, we demonstrate room temperature EP BEC in organic single-crystal microribbon natural cavities. The regularly shaped microribbons serve as waveguide Fabry–Pérot microcavities, in which efficient strong coupling between Frenkel excitons and photons leads to the generation of EPs at room temperature. The large exciton–photon coupling strength due to high exciton densities facilitates the achievement of EP BEC. Taking advantages of interactions in EP condensates and dimension confinement effects, we demonstrate the realization of controllable output of coherent light from the microribbons. We hope that the results will provide a useful enlightenment for using organic single crystals to construct miniaturized polaritonic devices.

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