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Terahertz field control of in-plane orbital order in La(0.5)Sr(1.5)MnO4.

Miller TA, Chhajlany RW, Tagliacozzo L, Green B, Kovalev S, Prabhakaran D, Lewenstein M, Gensch M, Wall S - Nat Commun (2015)

Bottom Line: Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition.Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field.Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation.

View Article: PubMed Central - PubMed

Affiliation: ICFO-Institut de Ciències Fotòniques, Av. Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.

ABSTRACT
In-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phases such as superconductivity; however, their origins are debated. Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition. Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field. Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation. Our results highlight the key role played by the Coulomb interaction in the control and manipulation of orbital order in the manganites and demonstrate a new way to use THz to understand and manipulate anisotropic phases in a potentially broad range of correlated materials.

No MeSH data available.


Related in: MedlinePlus

Temperature dependence of THz-induced orbital domain alignment.The 2D plot, (a) shows the THz-induced anisotropy signal when normalized by the incident power. Dark dashed lines correspond to the orbital, TOO, and magnetic, TN, ordering temperatures. White squares correspond to the onset of the THz-induced signal. THz alignment is only observed for T<TOO. As the temperature approaches TN the signal begins to decrease. For higher powers, the onset shifts to lower temperatures due to THz heating of the sample. Dashed white line is a cubic fit to the temperature shift. (b) The line-outs for the three indicated powers in a. The high-power signal is reproduced with an 85 K offset to demonstrate the heating effect. The solid black line shows R⊥ from Fig. 1c, indicating how the anisotropic signal changes with temperature.
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f3: Temperature dependence of THz-induced orbital domain alignment.The 2D plot, (a) shows the THz-induced anisotropy signal when normalized by the incident power. Dark dashed lines correspond to the orbital, TOO, and magnetic, TN, ordering temperatures. White squares correspond to the onset of the THz-induced signal. THz alignment is only observed for T<TOO. As the temperature approaches TN the signal begins to decrease. For higher powers, the onset shifts to lower temperatures due to THz heating of the sample. Dashed white line is a cubic fit to the temperature shift. (b) The line-outs for the three indicated powers in a. The high-power signal is reproduced with an 85 K offset to demonstrate the heating effect. The solid black line shows R⊥ from Fig. 1c, indicating how the anisotropic signal changes with temperature.

Mentions: To understand these observations, we measured a detailed power and temperature dependence. Figure 3a shows the temperature and power dependence of power-normalized THz-induced net anisotropy. On cooling below TOO, the anisotropic signal increases rapidly for moderate THz powers. This occurs in step with the total orbital order shown in Fig. 1c. This rapid increase is due to the increasing correlation length of domains that occurs as the sample cools. On further cooling, the induced anisotropy saturates at ∼200 K and then starts to diminish, with the signal almost gone below TN.


Terahertz field control of in-plane orbital order in La(0.5)Sr(1.5)MnO4.

Miller TA, Chhajlany RW, Tagliacozzo L, Green B, Kovalev S, Prabhakaran D, Lewenstein M, Gensch M, Wall S - Nat Commun (2015)

Temperature dependence of THz-induced orbital domain alignment.The 2D plot, (a) shows the THz-induced anisotropy signal when normalized by the incident power. Dark dashed lines correspond to the orbital, TOO, and magnetic, TN, ordering temperatures. White squares correspond to the onset of the THz-induced signal. THz alignment is only observed for T<TOO. As the temperature approaches TN the signal begins to decrease. For higher powers, the onset shifts to lower temperatures due to THz heating of the sample. Dashed white line is a cubic fit to the temperature shift. (b) The line-outs for the three indicated powers in a. The high-power signal is reproduced with an 85 K offset to demonstrate the heating effect. The solid black line shows R⊥ from Fig. 1c, indicating how the anisotropic signal changes with temperature.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595605&req=5

f3: Temperature dependence of THz-induced orbital domain alignment.The 2D plot, (a) shows the THz-induced anisotropy signal when normalized by the incident power. Dark dashed lines correspond to the orbital, TOO, and magnetic, TN, ordering temperatures. White squares correspond to the onset of the THz-induced signal. THz alignment is only observed for T<TOO. As the temperature approaches TN the signal begins to decrease. For higher powers, the onset shifts to lower temperatures due to THz heating of the sample. Dashed white line is a cubic fit to the temperature shift. (b) The line-outs for the three indicated powers in a. The high-power signal is reproduced with an 85 K offset to demonstrate the heating effect. The solid black line shows R⊥ from Fig. 1c, indicating how the anisotropic signal changes with temperature.
Mentions: To understand these observations, we measured a detailed power and temperature dependence. Figure 3a shows the temperature and power dependence of power-normalized THz-induced net anisotropy. On cooling below TOO, the anisotropic signal increases rapidly for moderate THz powers. This occurs in step with the total orbital order shown in Fig. 1c. This rapid increase is due to the increasing correlation length of domains that occurs as the sample cools. On further cooling, the induced anisotropy saturates at ∼200 K and then starts to diminish, with the signal almost gone below TN.

Bottom Line: Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition.Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field.Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation.

View Article: PubMed Central - PubMed

Affiliation: ICFO-Institut de Ciències Fotòniques, Av. Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.

ABSTRACT
In-plane anisotropic ground states are ubiquitous in correlated solids such as pnictides, cuprates and manganites. They can arise from doping Mott insulators and compete with phases such as superconductivity; however, their origins are debated. Strong coupling between lattice, charge, orbital and spin degrees of freedom results in simultaneous ordering of multiple parameters, masking the mechanism that drives the transition. Here we demonstrate that the orbital domains in a manganite can be oriented by the polarization of a pulsed THz light field. Through the application of a Hubbard model, we show that domain control can be achieved by enhancing the local Coulomb interactions, which drive domain reorientation. Our results highlight the key role played by the Coulomb interaction in the control and manipulation of orbital order in the manganites and demonstrate a new way to use THz to understand and manipulate anisotropic phases in a potentially broad range of correlated materials.

No MeSH data available.


Related in: MedlinePlus