Gapless semiconductors: A new class of substances

Tsidilkovskii, I. M.

doi:10.1070/pu1982v025n10abeh004619

Cited by 5 publications

(10 citation statements)

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“…2). The scheme of electron bands of HgTe 1-x S x compound at G-point of Brillouin zone [2] under variation of content x and pressure P. The notation is described in text Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

“…1) [1,2]. The peculiarity of the HgTe 1-x S x system in comparison with the similar HgSe 1-x S x one [3] consists in the presence of several types of charge carriers, such that under T, B, P variation a change of the sign of Hall effect and thermo-EMF S occur [1,2,4]. 1).…”

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confidence: 99%

“…The application of hydrostatic pressure P to zero-gap semiconductors HgX leads to a decreasing absolute value of gap E g between the conducting band G 8 and the light-hole band G 6 , contrary to the open-gap semiconductors with the same sphalerite structure, where this forbidden gap is rising under pressure [1,2]. The structural phase transition in ternary mercury chalcogenides starts at P !…”

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confidence: 99%

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Raman Spectra and Electronic Properties of HgTeS Crystals at High Pressure

Ponosov

Shchennikov

Mogilenskikh

et al. 2001

phys. stat. sol. (b)

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The results of transverse magnetoresistance (MR) and Raman spectrum (RS) measurements (in the region 80-160 cm -1 ) of Hg 1-x Te x S crystals (0.04 x 0.6) at room temperature and high pressure P up to 1.6 GPa are presented. The galvanomagnetic measurements show the change of electronic structure and charge carrier concentration as the sulphur content is rising. The increasing of MR under P and, hence, the increase of electron mobility agree with the certain model of electronic structure of gapless semiconductors. Three HgTe-like phonon Raman modes were observed near about 90, 120 and 140 cm -1 , and one mode near 100 cm -1 , which was shifted to lower frequencies in the sulphur-rich samples in accordance with theoretical predictions. At P ¼ 1.6 GPa, above the onset of pressure-induced phase, two a-HgS like peaks near 90 cm -1 were observed.

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“…2). The scheme of electron bands of HgTe 1-x S x compound at G-point of Brillouin zone [2] under variation of content x and pressure P. The notation is described in text Fig. 1.…”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Raman Spectra and Electronic Properties of HgTeS Crystals at High Pressure

Ponosov

Shchennikov

Mogilenskikh

et al. 2001

phys. stat. sol. (b)

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“…Examples of gapless semiconductors include graphene, HgTe, α-Sn and some half-metallic Heusler compounds. [8][9][10] Figure 1(a) illustrates the electronic density of states (DOS) for the majority and minority spin components in a gapless semiconductor, where the gap for both the conduction and valence states vanishes at the Fermi energy. In the case where one of the spin bands develops a gap, shown in Fig.…”

Section: Introductionmentioning

confidence: 99%

Antiferromagnetic phase of the gapless semiconductorV3Al

et al. 2015

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Discovering new antiferromagnetic compounds is at the forefront of developing future spintronic devices without fringing magnetic fields. The antiferromagnetic gapless semiconducting D0 3 phase of V 3 Al was successfully synthesized via arc-melting and annealing. The antiferromagnetic properties were established through synchrotron measurements of the atom-specific magnetic moments, where the magnetic dichroism reveals large and oppositelyoriented moments on individual V atoms. Density functional theory calculations confirmed the stability of a type G antiferromagnetism involving only two-third of the V atoms, while the remaining V atoms are nonmagnetic. Magnetization, x-ray diffraction and transport measurements also support the antiferromagnetism. This archetypal gapless semiconductor may be considered as a cornerstone for future spintronic devices containing antiferromagnetic elements.

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“…We also determined that in the case of superconductors with magnetic impurities, the energy gap magnitude becomes zero somewhat earlier than the superconductivity disappears, since their energy spectrum has pairs with different binding energy including that arbitrarily close to zero. Such gapless superconductors [73] are characterized by several unusual properties, in particular, a linear heat capacity dependence on the temperature, as in case of normal metals. Superconductors with magnetic impurities possess other interesting properties, for example, the theoretical possibility for the existence of a phase that is simultaneously superconducting and ferromagnetic, which can also enhance the superconducting transition temperature [74].…”

Section: Energy Spectrum Of Superconducting Materials Energy 'Gap' Amentioning

confidence: 99%

High-temperature superconductivity: From macro- to nanoscale structures

Коваленко¹

2016

Nanosystems: Phys. Chem. Math.

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The analysis of achievements, problems and prospects of high-temperature superconductivity (HTSC) in the macro-and nanostructured materials has been given. The main experimental results and theoretical models describing the physical mechanisms of the superconductivity appearance at phenomenological and microscopic levels, including change in the energy spectrum of atoms in these materials with the advent of the 'superconducting' gap at temperatures below the critical transition, as well as the above-critical temperature 'pseudo-gap' have been analyzed.Although the origin of the pseudo-gap is not completely understood, it can be considered as an independent phase transition in the substance prior to the transition to the zero resistance state and insusceptibility (or insensitivity) to external magnetic field in high-temperature superconductors. Features of multi-gap and gapless superconducting materials as well as their ability to further increase the temperature of supercritical transition are discussed. Large resources to create the necessary electron and phonon spectra in the process of high-temperature superconductivity formation are associated with the use of nanoscale structures and nanoparticles of conductors and dielectrics. Electrical conductive contacts between nanoparticles and tunnel chains of nanoclusters, where delocalized electron spectra form similar energy shells to the atomic or nuclear shells, play a significant part here. It is required to further investigate the occurrence of high-temperature superconductivity at the level of interphase layers (non-autonomous phases) in nanostructures containing a large fraction of the substance in this condition. It is essential to develop adequate methods for synthesis of nanoparticles of variable size, structure and morphology, as well as techniques for their consolidation that would ensure the preservation of superconductivity of individual nanoparticles, their chemical, thermal, magnetic and current stability in the dissipative processes with functional and fluctuation effects.

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Gapless semiconductors: A new class of substances

Cited by 5 publications

References 0 publications

Raman Spectra and Electronic Properties of HgTeS Crystals at High Pressure

Raman Spectra and Electronic Properties of HgTeS Crystals at High Pressure

Antiferromagnetic phase of the gapless semiconductorV3Al

High-temperature superconductivity: From macro- to nanoscale structures

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