Figure 3 - available via license: Creative Commons Attribution 4.0 International
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The top view of the anti-ferroelectric square lattice of alternating dipolar excitons or biexcitons. White (black) circles correspond to dipoles whose orientation points up (down). Straight lines are guides for eye.
Source publication
We study the gas of indirect dipolar excitons created by an interband illumination of pentalayer WSe$_2$/MoSe$_2$/WSe$_2$/MoSe$_2$/WSe$_2$. We show that two colinear indirect excitons bind into a linear biexciton with twice larger orthogonal to the pentalayer dipole moment. Two biexcitons with opposite dipolar directions attract each other at large...
Contexts in source publication
Context 1
... located in the middle layer approach each other. It was shown that the interaction energy of directed up and down dipolar excitons has a minimum near n −1/2 = 2.8d, where d ∼ 7 nm [6] is the distance between two layers. The ground state of these excitons in a WMW device is a staggered square lattice of alternating up and down dipoles (see Fig. 3). The interaction energy per exciton of such a crystal has minimum at the concentration n c = 0.12d −2 . Therefore, at low illumination intensities, when n < n c , all excitons condense into droplets of the density n c , which do not interact with each ...
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... moments attract each other at large distances. At small distances they strongly repel each other because they have charges of the same sign in three middle layers. This competition of attraction and repulsion leads to a anti-ferroelectric biexciton crystal in a WMWMW pentalayer. The side and the top view of this crystal are shown in Fig. 5 and Fig. 3. Figure 5. Pentalayer WSe2/MoSe2/WSe2/MoSe2/WSe2 device. WSe2 layers are red and MoSe2 layers are blue. When the device is illuminated at low temperatures, linear biexcitons with alternating orientations are created. Biexcitons form a staggered square lattice, and the top view of which is shown in Fig. ...
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... of this crystal are shown in Fig. 5 and Fig. 3. Figure 5. Pentalayer WSe2/MoSe2/WSe2/MoSe2/WSe2 device. WSe2 layers are red and MoSe2 layers are blue. When the device is illuminated at low temperatures, linear biexcitons with alternating orientations are created. Biexcitons form a staggered square lattice, and the top view of which is shown in Fig. ...
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... we calculate the Coulomb energy cost ∆U of inverting the orientation of a dipolar biexciton in a WMWMW device, which can be done by applying an electric field in exper- Figure 6. The full black curve shows the dimensionless electrostatic energy per biexciton U/(e 2 /κd) in a staggered lattice (c.f. Fig. 3) versus the dimensionless biexciton density nd 2 in a WMWMW device. The blue dashed curve reproduces the electrostatic energy of a staggered lattice per exciton versus the dimensionless density of excitons nd 2 in a WMW device ...
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... the orientation of biexcitons alternates between neighboring sites which forms two sublattices labeled by • (up) and • (down) in Fig. 3, the electrostatic energy consists of summa- Figure 7. The full black curve shows the dimensionless energy cost ∆U/(e 2 /κd) of inverting the orientation of a biexciton in a pentalayer device (c.f. Fig. 5) by moving a hole from the top WSe2 layer to the bottom WSe2 layer versus the dimensionless biexciton density nd 2 . The blue dashed ...
