Magnetoabsorption in Single-Crystal HgCr<sub>2</sub>Se<sub>4</sub>

Arai, Toshihiro; Wakaki, Moriaki; Onari, Seiichiro; Kudo, Keiei; Satoh, T.; Tsushima, T.

doi:10.1143/jpsj.34.68

Cited by 64 publications

(23 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1(b)]. 23,29 At temperatures near the Curie temperature (T C ≈ 105 K), especially on the paramagnetic side, giant negative magnetoresistances are observed, as illustrated in Fig. 1(c-d).…”

Section: Resultsmentioning

confidence: 91%

“…Such a scaling behavior is expected for the critical region of a second-order magnetic phase transition. 31 It is important to note that the magnetic properties are dominated by the superexchange-coupled Cr 3+ ions, 23 since the conduction electrons are outnumbered by Cr 3+ ions by four orders of magnitude. From the fits for extracting critical exponents β and γ, we obtain T C =105.35 K, which is close to the maximum in the temperature derivative of the zero-field resistivity, dρ xx, 0 /dT , as shown in Fig.…”

Section: (C)mentioning

confidence: 99%

See 1 more Smart Citation

Spin correlations and colossal magnetoresistance inHgCr2Se4

Lin

Shi

et al. 2016

Phys. Rev. B

View full text Add to dashboard Cite

This study aims to unravel the mechanism of colossal magnetoresistance (CMR) observed in n-type HgCr2Se4, in which low-density conduction electrons are exchange-coupled to a threedimensional Heisenberg ferromagnet with a Curie temperature TC ≈ 105 K. Near room temperature the electron transport exhibits an ordinary semiconducting behavior. As temperature drops below T * ≃ 2.1 TC, the magnetic susceptibility deviates from the Curie-Weiss law, and concomitantly the transport enters an intermediate regime exhibiting a pronounced CMR effect before a transition to metallic conduction occurs at T < TC . Our results suggest an important role of spin correlations not only near the critical point, but also for a wide range of temperatures (TC < T < T * ) in the paramagnetic phase. In this intermediate temperature regime the transport undergoes a percolation type of transition from isolated magnetic polarons to a continuous network when temperature is lowered or magnetic field becomes stronger.

show abstract

Section: Resultsmentioning

confidence: 91%

Section: (C)mentioning

confidence: 99%

Spin correlations and colossal magnetoresistance inHgCr2Se4

Lin

Shi

et al. 2016

Phys. Rev. B

View full text Add to dashboard Cite

show abstract

“…The optical properties of HgCr 2 Se 4 are similar to those of direct band gap semiconductors. The band gap of HgCr 2 Se 4 decreases from E g = 0.84 eV at room temperature (RT) to 0.26 eV at 4.2 K [12,22,24,25]. This is of the same order in comparison with the band gap in pure CdCr 2 Se 4 (1.3 eV at RT) [26] and HgGa 2 Se 4 (1.93 eV at RT) [27].…”

Section: Sample and Experimental Techniquementioning

confidence: 81%

Static and time-resolved mid-infrared spectroscopy of Hg_0.95Cd_0.05Cr₂Se₄spinel

Barsaume

Telegin

Sukhorukov

et al. 2017

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

Static and time-resolved mid-infrared spectroscopy of ferromagnetic single crystal HgCdCrSe was performed below the absorption edge, in order to reveal the origin of the electronic transitions contributing to the magneto-optical properties of this material. The mid-infrared spectroscopy reveals a strong absorption peak around 0.236 eV which formerly was assigned to a transition within the selenide-chromium complexes ([Formula: see text] -Cr). To reveal the sensitivity of the transition to the magnetic order, we performed the studies in a temperature range across the Curie temperature and magnetic fields across the value at which the saturation of ferromagnetic magnetization occurs. Despite the fact that the Curie temperature of this ferromagnetic semiconductor is around 107 K, the intensity of the mid-infrared transition reduces substantially increasing the temperature, so that already at 70 K the absorption peak is hardly visible. Such a dramatic decrease of the oscillator strength is observed simultaneously with the strong red-shift of the absorption edge in the magnetic semiconductor. Employing a time-resolved pump-and-probe technique enabled us to determine the lifetime of the electrons in the excited state of this optical transition. In the temperature range from 7 K to 80 K, the lifetime changes from 3 ps to 6 ps. This behavior agrees with the phenomenon of giant oscillator strength described earlier for weakly bound excitons in nonmagnetic semiconductors.

show abstract

“…It is a ferromagnetic material with the spinel structure17, and exhibits novel and unusual properties, including anomalous Hall effect18, giant magnetoresistance19, red shift of the optical absorption edge20, semiconducting character in the paramagnetic state and semimetal character in its ferromagnetic state192122. Its Fermi arc structure has not been confirmed by any ARPES experiments.…”

mentioning

confidence: 99%

Theoretical study of HgCr2Se3.5Te0.5: a doping-site-dependent semimetal

Jin

2016

Sci Rep

View full text Add to dashboard Cite

Weyl semimetals have recently attracted enormous attention due to their unusual features. So far, this novel state has been predicted theoretically and confirmed experimentally in several materials, such as HgTe, LaPtBi, Y2Ir2O7, TaAs, TaP, NbAs, NbP and HgCr2Se4. Doping plays an important role in the research of condensed-matter materials. However, its influence on the Weyl semimetal has been little investigated. Here, we present detailed first-principles and theoretical studies on HgCr2Se4 with doping of Te atoms at the Se sites. A special case where only one pair of crossing points locates at the Fermi level is realized in HgCr2Se3.5Te0.5 where one of the Se atoms in the primitive unit cell is replaced by a Te atom. A further study of k·p theory shows that the two points constitute a pair of Weyl nodes with opposite chiralities in the momentum space, and only one edge state and one single Fermi arc are obtained at each boundary of a film. Moreover, through investigations and analyses of different doping cases of HgCr2Se3.5Te0.5, we find that when the type of doping induces inversion symmetry or positional disorder, the Weyl nodes transform into Dirac points resulting in a change from a Weyl semimetal to a Dirac semimetal.

show abstract

Magnetoabsorption in Single-Crystal HgCr₂Se₄

Cited by 64 publications

References 14 publications

Spin correlations and colossal magnetoresistance inHgCr2Se4

Spin correlations and colossal magnetoresistance inHgCr2Se4

Static and time-resolved mid-infrared spectroscopy of Hg_0.95Cd_0.05Cr₂Se₄spinel

Theoretical study of HgCr2Se3.5Te0.5: a doping-site-dependent semimetal

Contact Info

Product

Resources

About

Magnetoabsorption in Single-Crystal HgCr2Se4

Cited by 64 publications

References 14 publications

Spin correlations and colossal magnetoresistance inHgCr2Se4

Spin correlations and colossal magnetoresistance inHgCr2Se4

Static and time-resolved mid-infrared spectroscopy of Hg0.95Cd0.05Cr2Se4spinel

Theoretical study of HgCr2Se3.5Te0.5: a doping-site-dependent semimetal

Contact Info

Product

Resources

About

Magnetoabsorption in Single-Crystal HgCr₂Se₄

Static and time-resolved mid-infrared spectroscopy of Hg_0.95Cd_0.05Cr₂Se₄spinel