Dynamic negative capacitance response in GeTe Rashba ferroelectric

Орлова, Н. Н.; Timonina, A. V.; Kolesnikov, N. N.; Deviatov, E. V.

doi:10.1016/j.physb.2022.414358

Cited by 4 publications

(8 citation statements)

References 30 publications

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“…160). [30] The gate-dependent ferroelectric polarization was also demonstrated in capacitance measurements, [36] the results confirmed giant Rashba splitting [30] in our GeTe single crystals.…”

supporting

confidence: 82%

“…In non-magnetic topological semimetals, the Berry curvature is defined by Weyl nodes separation due to the breaking of inversion symmetry, [12,13] so the Berry curvature is directly connected with the Rashba parameter 𝛼R in GeTe. On the other hand, the dependence of the Rashba parameter on the ferroelectric polarization is known for giant Rashba splitting in GeTe from theoretical [30] and experimental [35,36] investigations. Even for relatively thick flakes, ferroelectric polarization is sensitive [36,45] to the gate electric field, since the relevant (bottom) flake surface is directly adjoined to the SiO2 layer.…”

Section: (B) As the Gate Voltage Scan 𝑈 2𝜔mentioning

confidence: 99%

“…On the other hand, the dependence of the Rashba parameter on the ferroelectric polarization is known for giant Rashba splitting in GeTe from theoretical [30] and experimental [35,36] investigations. Even for relatively thick flakes, ferroelectric polarization is sensitive [36,45] to the gate electric field, since the relevant (bottom) flake surface is directly adjoined to the SiO2 layer. Variation of 𝛼R can be as large [30,36] as 20% in the gate voltage range of Fig.…”

Section: (B) As the Gate Voltage Scan 𝑈 2𝜔mentioning

confidence: 99%

“…[34] As an additional advantage, the Rashba parameter is known to depend on the external electric field in GeTe. [30,35,36] In this Letter, we experimentally investigate nonlinear Hall effect as zero-frequency and second-harmonic transverse voltage responses to ac electric current for topological semimetal GeTe. We confirm that electron concentration is not gate-sensitive in thick conductive flakes due to the gate field screening by bulk carriers in GeTe.…”

mentioning

confidence: 99%

“…The p-doped bulk Si layer under the SiO2 surface serves as a gate electrode to apply the gate electric field through the 200-nm-thick SiO2 layer. Even for relatively thick flakes, ferroelectric polarization is sensitive [36,45] to the gate electric field, since the relevant (bottom) flake surface is directly adjoined to the SiO2 layer. We check it by an electrometer in which there is no measurable leakage current in the gate voltage range ±50 V.…”

mentioning

confidence: 99%

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Gate-Dependent Nonlinear Hall Effect at Room Temperature in Topological Semimetal GeTe

Орлова¹,

Timonina²,

Kolesnikov³

et al. 2023

Chinese Phys. Lett.

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We experimentally investigate non-linear Hall effect as zero-frequency and second-harmonic transverse voltage responses to ac electric current for topological semimetal GeTe. A thick single-crystal GeTe flake is placed on the Si/SiO2 substrate, where the p-doped Si layer serves as a gate electrode. We confirm, that electron concentration is not gate-sensitive in thick GeTe flakes due to the gate field screening by bulk carriers. In contrast, by transverse voltage measurements, we demonstrate that the non-linear Hall effect shows pronounced dependence on the gate electric field at room temperature. Since the non-linear Hall effect is a direct consequence of a Berry curvature dipole in topological media, our observations indicate that Berry curvature can be controlled by the gate electric field. This experimental observation can be understood as a result of the known dependence of giant Rashba splitting on the external electric field in GeTe. For possible applications, the zero-frequency gate-controlled non-linear Hall effect can be used for the efficient broad-band rectification.

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supporting

confidence: 82%

Section: (B) As the Gate Voltage Scan 𝑈 2𝜔mentioning

confidence: 99%

Section: (B) As the Gate Voltage Scan 𝑈 2𝜔mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Gate-Dependent Nonlinear Hall Effect at Room Temperature in Topological Semimetal GeTe

Орлова¹,

Timonina²,

Kolesnikov³

et al. 2023

Chinese Phys. Lett.

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Efficient magnetic switching in a correlated spin glass

Krempaský,

Springholz,

D’Souza

et al. 2023

Nat Commun

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The interplay between spin-orbit interaction and magnetic order is one of the most active research fields in condensed matter physics and drives the search for materials with novel, and tunable, magnetic and spin properties. Here we report on a variety of unique and unexpected observations in thin multiferroic Ge1−xMnxTe films. The ferrimagnetic order parameter in this ferroelectric semiconductor is found to switch direction under magnetostochastic resonance with current pulses many orders of magnitude lower as for typical spin-orbit torque systems. Upon a switching event, the magnetic order spreads coherently and collectively over macroscopic distances through a correlated spin-glass state. Utilizing these observations, we apply a novel methodology to controllably harness this stochastic magnetization dynamics.

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Reentrant Proximity-Induced Superconductivity for GeTe Semimetal

Esin,

Kazmin,

Barash

et al. 2023

Jetp Lett.

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We experimentally investigate charge transport in In-GeTe and In-GeTe-In proximity devices, which are formed as junctions between superconducting indium leads and thick single crystal flakes of α-GeTe topological semimetal. We observe nonmonotonic effects of the applied external magnetic field, including reentrant superconductivity in In-GeTe-In Josephson junctions: supercurrent reappears at some finite magnetic field. For a single In-GeTe Andreev junction, the superconducting gap is partially suppressed in zero magnetic field, while the gap is increased nearly to the bulk value for some finite field before its full suppression. We discuss possible reasons for the results obtained, taking into account spin polarization of Fermi arc surface states in topological semimetal α-GeTe with a strong spin-orbit coupling. In particular, the zero-field surface state spin polarization partially suppresses the superconductivity, while it is recovered due to the modified spin-split surface state configuration in finite fields. As an alternative possible scenario, the transition into the Fulde–Ferrell–Larkin–Ovchinnikov state is discussed. However, the role of strong spin-orbit coupling in forming the nonmonotonic behavior has not been analyzed for heterostructures in the Fulde–Ferrell–Larkin–Ovchinnikov state, which is crucial for junctions involving GeTe topological semimetal.

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Dynamic negative capacitance response in GeTe Rashba ferroelectric

Cited by 4 publications

References 30 publications

Gate-Dependent Nonlinear Hall Effect at Room Temperature in Topological Semimetal GeTe

Gate-Dependent Nonlinear Hall Effect at Room Temperature in Topological Semimetal GeTe

Efficient magnetic switching in a correlated spin glass

Reentrant Proximity-Induced Superconductivity for GeTe Semimetal

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