A measurable force driven by an excitonic condensate

Hakioğlu, T.; Özgün, Ege; Günay, Mehmet

doi:10.1063/1.4873377

Cited by 6 publications

(11 citation statements)

References 27 publications

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“…The remarkable experiments on exciton BEC have motivated rapid development of theoretical ideas 38 . Many interesting effects have been predicted for exciton BECs: existence of non-dissipative electric currents 39 and internal Josephson effect 40 , roton instability 41 , autolocalization 42 and (mesoscopic 43 ) supersolidity 44,45 , BKT transition 46 (crossover 47 ) and vortex formation 48 , features of angle-resolved photoluminescence 49 and nonlinear optical phenomena 50 , as well as topological excitons 51 , dipole superconductivity 52 , and Casimir effect 53 . Another interesting topic are exciton spin effects that have been predicted to lead to a multicomponent BEC 22 , which has been recently observed experimentally 54 .…”

Section: Introductionmentioning

confidence: 99%

Anisotropic superfluidity of two-dimensional excitons in a periodic potential

2017

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We study anisotropies of helicity modulus, excitation spectrum, sound velocity and angle-resolved luminescence spectrum in a two-dimensional system of interacting excitons in a periodic potential. Analytical expressions for anisotropic corrections to the quantities characterizing superfluidity are obtained. We consider particularly the case of dipolar excitons in quantum wells. For GaAs/AlGaAs heterostructures as well as MoS2/hBN/MoS2 and MoSe2/hBN/WSe2 transition metal dichalcogenide bilayers estimates of the magnitude of the predicted effects are given. We also present a method to control superfluid motion and to determine the helicity modulus in generic dipolar systems.

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Section: Introductionmentioning

confidence: 99%

Anisotropic superfluidity of two-dimensional excitons in a periodic potential

2017

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“…Here the EC force weakens as the critical point is approached, whereas in the pure EC system in Ref. 21 η D/a t 1 /t 0 =0, λ 0 =1.12 t 1 /t 0 =0, λ 0 =1.20 t 1 /t 0 =0.04, λ 0 =1.20…”

Section: Ec-force Driving the Lattice Deformationsmentioning

confidence: 92%

“…The concept of a force arising from condensation is not new to this work. The EC-force was first predicted in numerical 20 and semi-analytical 21 energy E H and the Fermi energy E F are both in the 10meV range. However, the CDW and EC interaction strengths, the hopping energy scale t 0 ≃ 100 − 200meV and the critical temperatures of 150 − 200K in the TMDC materials are at least an order of magnitude larger than the system studied in Ref's20, 21.…”

Section: Introductionmentioning

confidence: 95%

CDW-Exciton Condensate Competition and a Condensate Driven Force

Özgün

Hakioğlu

2016

J. Phys. Soc. Jpn.

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We examine the competition between the charge-density wave (CDW) instability and the excitonic condensate (EC) in spatially separated layers of electrons and holes. The CDW and the EC order parameters (OPs), described by two different mechanisms and hence two different transition temperatures $T^{CDW}_c$ and $T^{EC}_c$, are self-consistently coupled by a microscopic mean field theory. We discuss the results in our model specifically focusing on the transition-metal dichalcogenides which are considered as the most typical examples of strongly coupled CDW/EC systems with atomic layer separations where the electronic energy scales are large with the critical temperatures in the range $T^{EC}_c \sim T^{CDW}_c \sim 100-200 K$. An important consequence of this is that the excitonic energy gap, hence the condensed free energy, vary with the layer separation resulting in a new type of force ${\cal F}_{EC}$. We discuss the possibility of this force as the possible driver of the structural lattice deformation observed in some TMDCs with a particular attention on the $ 1 {\it T}$-$TiSe_2$ below $200 K$.Comment: 8 pages, 5 figure

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“…Since the induced potential is longrange, the nature of the emerging force also appears longrange when the layer separation is smaller than the critical point (D c ) and it vanishes beyond that point (D>D c ). This result (interlayer pairing force) can be realized in excitonic condensate systems [20,21] as well as the bilayer graphene structures [22] when the sufficient pairing be- tween different layers is present. Finally, we discuss that the work done by this force can be used in the realization of the quantum heat-engines.…”

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confidence: 85%

Emergent force in a bilayer superfluid Bose-Fermi mixture

Günay¹

2019

Preprint

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We investigate a system of two-atomic species in mixed dimensions, in which one species is spread in a three-dimensional space and the other species is confined in two parallel layers. The presence of atoms in 3-dimensions creates an induced potential for the ones confined in layers. Depending on the effective scattering length and the layer separation, the formation of p-wave pairing within the same layer or s-wave pairing between different layers has been suggested. It is shown that these pairs cannot coexist when time-reversal symmetry (TRS) is on, and there appears a transition from p-wave to s-wave as the ratio of the layer separation and the effective scattering length decreases. With the formation of the inter-layer pairing, we find an emergent force to be present at the critical point and show that it can be derived from the ground state energy. This result offers a tool for experimentally realizing such transitions, and can find notable potential in the field of quantumthermodynamics.

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A measurable force driven by an excitonic condensate

Cited by 6 publications

References 27 publications

Anisotropic superfluidity of two-dimensional excitons in a periodic potential

Anisotropic superfluidity of two-dimensional excitons in a periodic potential

CDW-Exciton Condensate Competition and a Condensate Driven Force

Emergent force in a bilayer superfluid Bose-Fermi mixture

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