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Quantum capacitance of an ultrathin topological insulator film in a magnetic field.

Tahir M, Sabeeh K, Schwingenschlögl U - Sci Rep (2013)

Bottom Line: We present a theoretical study of the quantum magnetocapacitance of an ultrathin topological insulator film in an external magnetic field.This leads to a change in the character of the magnetocapacitance at the charge neutrality point.In addition, we address the crossover from perpendicular to parallel magnetic field and find consistency with recent experimental data.

View Article: PubMed Central - PubMed

Affiliation: PSE Division , KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia.

ABSTRACT
We present a theoretical study of the quantum magnetocapacitance of an ultrathin topological insulator film in an external magnetic field. The study is undertaken to investigate the interplay of the Zeeman interaction with the hybridization between the upper and lower surfaces of the thin film. Determining the density of states, we find that the electron-hole symmetry is broken when the Zeeman and hybridization energies are varied relative to each other. This leads to a change in the character of the magnetocapacitance at the charge neutrality point. We further show that in the presence of both Zeeman interaction and hybridization the magnetocapacitance exhibits beating at low and splitting of the Shubnikov de Haas oscillations at high perpendicular magnetic field. In addition, we address the crossover from perpendicular to parallel magnetic field and find consistency with recent experimental data.

No MeSH data available.


Quantum capacitance as a function of the magnetic field at T = 0 K and hybridization energy 4 meV.
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f3: Quantum capacitance as a function of the magnetic field at T = 0 K and hybridization energy 4 meV.

Mentions: In Fig. 3 we address the SdH oscillations in CQ. The following parameters are used: Γ = 0.3 meV, T = 0 K, ne = 4 × 1015 m−2, v = 3 × 105 ms−1, and Δh = 4 meV. For low and high magnetic field we observe a beating pattern and a splitting of the SdH oscillations, respectively. Both occurs due to interference of the SdH oscillations at two different frequencies and therefore is a consequence of the splitting of the LLs for finite Zeeman interaction and hybridization. The beating pattern vanishes once the Zeeman interaction dominates the hybridization. For the chosen parameters this occurs at a magnetic field of about 1.5 T. Above this value we find a well resolved splitting of the SdH oscillations in Fig. 3. A similar beating pattern and splitting of SdH oscillations in the longitudinal resistivity is seen in Ref. 44, where it occurs because of splitting of the LLs as a result of a broken inversion symmetry due to substrate effects. The sample investigated in this reference is thick and hybridization effects are ruled out.


Quantum capacitance of an ultrathin topological insulator film in a magnetic field.

Tahir M, Sabeeh K, Schwingenschlögl U - Sci Rep (2013)

Quantum capacitance as a function of the magnetic field at T = 0 K and hybridization energy 4 meV.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3569631&req=5

f3: Quantum capacitance as a function of the magnetic field at T = 0 K and hybridization energy 4 meV.
Mentions: In Fig. 3 we address the SdH oscillations in CQ. The following parameters are used: Γ = 0.3 meV, T = 0 K, ne = 4 × 1015 m−2, v = 3 × 105 ms−1, and Δh = 4 meV. For low and high magnetic field we observe a beating pattern and a splitting of the SdH oscillations, respectively. Both occurs due to interference of the SdH oscillations at two different frequencies and therefore is a consequence of the splitting of the LLs for finite Zeeman interaction and hybridization. The beating pattern vanishes once the Zeeman interaction dominates the hybridization. For the chosen parameters this occurs at a magnetic field of about 1.5 T. Above this value we find a well resolved splitting of the SdH oscillations in Fig. 3. A similar beating pattern and splitting of SdH oscillations in the longitudinal resistivity is seen in Ref. 44, where it occurs because of splitting of the LLs as a result of a broken inversion symmetry due to substrate effects. The sample investigated in this reference is thick and hybridization effects are ruled out.

Bottom Line: We present a theoretical study of the quantum magnetocapacitance of an ultrathin topological insulator film in an external magnetic field.This leads to a change in the character of the magnetocapacitance at the charge neutrality point.In addition, we address the crossover from perpendicular to parallel magnetic field and find consistency with recent experimental data.

View Article: PubMed Central - PubMed

Affiliation: PSE Division , KAUST, Thuwal 23955-6900, Kingdom of Saudi Arabia.

ABSTRACT
We present a theoretical study of the quantum magnetocapacitance of an ultrathin topological insulator film in an external magnetic field. The study is undertaken to investigate the interplay of the Zeeman interaction with the hybridization between the upper and lower surfaces of the thin film. Determining the density of states, we find that the electron-hole symmetry is broken when the Zeeman and hybridization energies are varied relative to each other. This leads to a change in the character of the magnetocapacitance at the charge neutrality point. We further show that in the presence of both Zeeman interaction and hybridization the magnetocapacitance exhibits beating at low and splitting of the Shubnikov de Haas oscillations at high perpendicular magnetic field. In addition, we address the crossover from perpendicular to parallel magnetic field and find consistency with recent experimental data.

No MeSH data available.