Density of States and Its Local Fluctuations Determined by Capacitance of Strongly Disordered Graphene

Li, Wei; Chen, Xiaolong; Wang, Lin; He, Yuheng; Wu, Zefei; Cai, Yuan; Zhang, Mingwei; Wang, Yan; Han, Yu; Lortz, Rolf; Zhang, Zhao-Qing; Sheng, Ping; Wang, Ning

doi:10.1038/srep01772

Cited by 24 publications

(17 citation statements)

References 42 publications

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“…As shown in Figure 1, the total capacitance C tg , in a series of the oxide layer capacitance C ox and graphene quantum capacitance C q , was measured by an integrated capacitance bridge for high sensitivity. This capacitance bridge delivered extremely high resolution of atto farad (aF) under very small excitation (~0.1 mV) driving any possible parasitic capacitance by a high mobility electron transistor (HMET)262735384041.…”

Section: Methodsmentioning

confidence: 99%

Negative Quantum Capacitance Induced by Midgap States in Single-layer Graphene

Wang

Chen

et al. 2013

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We demonstrate that single-layer graphene (SLG) decorated with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance. The Ag adatoms act as resonant impurities and form nearly dispersionless resonant impurity bands near the charge neutrality point (CNP). Resonant impurities quench the kinetic energy and drive the electrons to the Coulomb energy dominated regime with negative compressibility. In the absence of a magnetic field, negative quantum capacitance is observed near the CNP. In the quantum Hall regime, negative quantum capacitance behavior at several Landau level positions is displayed, which is associated with the quenching of kinetic energy by the formation of Landau levels. The negative quantum capacitance effect near the CNP is further enhanced in the presence of Landau levels due to the magnetic-field-enhanced Coulomb interactions.

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Section: Methodsmentioning

confidence: 99%

Negative Quantum Capacitance Induced by Midgap States in Single-layer Graphene

Wang

Chen

et al. 2013

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“…The typical medium approaches assume that the typical density of states (TDoS), when appropriately defined, acts as the "proper" order parameter for the ALT. Such an assumption is well justified not only for the non-interacting case [26][27][28] but also in the presence of interactions, as shown experimentally [9,29]. The typical medium theory (TMT) of Dobrosavljević et al [27] is a special case of the TMDCA when the cluster size N c = 1.…”

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confidence: 89%

“…Conclusions-Based on experiment, theory, and simulations, there is a growing consensus that the local density of states in a disordered system develops a highly skewed [49], log-normal distribution [9,29,50] with a typical value given by the geometric mean that vanishes at the localization transition, and hence, acts as an order parameter for the ALT. New mean field theories for localization, including the TMT and its cluster extension, the TMDCA, have been proposed.…”

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confidence: 99%

Metal-insulator transition in a weakly interacting disordered electron system

et al. 2015

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The interplay of interactions and disorder is studied using the Anderson-Hubbard model within the typical medium dynamical cluster approximation. Treating the interacting, non-local cluster self-energy (Σc[G](i, j = i)) up to second order in the perturbation expansion of interactions, U 2 , with a systematic incorporation of non-local spatial correlations and diagonal disorder, we explore the initial effects of electron interactions (U ) in three dimensions. We find that the critical disorder strength (W Introduction.-The metal-insulator transition (MIT) driven by random impurity has been an important topic in physics since the pioneer work by Anderson [1]. A significant advance in the MIT theory is achieved by studying it in the context of critical phenomena. Concepts from scaling, renormalization group (RG), and random matrix theory are used to understand the mechanism of localization at different dimensions for different symmetry classes [2][3][4][5]. It has been demonstrated that an infinitesimal amount of disorder can lead to localization for the models in the orthogonal class at lower (one and two) dimensions, whereas there is a MIT for three dimensions (3D) [2]. In 3D, a sharp mobility edge separating localized and delocalized states develop as disorder strength increases [6].While the MIT of non-interacting systems by now is fairly well understood [4,5,7], earlier studies suggested that interaction could play an important role in the MIT [8]. Over the last few decades, experimental works ranging from doped semiconductors [6, 9, 10], perovskite compounds [11][12][13][14][15]), to cold atoms in optical lattices [16][17][18][19] have highlighted the importance of the interplay of disorder (W ) [1,2,4,5] and interactions (U ) [6].At the Fermi level, Altshuler-Aronov [20] showed that interactions can induce a square-root and logarithmic singularity in two and three dimensions, respectively, while Efros-Shklovskii demonstrated the Coulomb gap [21]. Field theory perturbative RG method and diagrammatic theory which go beyond the Hartree-Fock approximations have suggested a metallic state for two dimensions [22,23]. The recent RG work by Finkelstein and co-workers has further indicated the possibility of a MIT for a model with degenerate valleys [24], the validity of which was confirmed through experiments in SiMOSFETs [24,25].In this letter, we focus on the system with weak local interactions on disorder systems in 3D. Our approach is

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“…Studies using well-defined samples are vital, where there are no contributions from the production or transfer process. Information on the electrical properties of the material would aid in determining the local DOS [94] and hence provide a greater ability to tune the electrode properties for the desired applications.…”

Section: Capacitance Of Graphene Electrodesmentioning

confidence: 99%