Electronic structure and magnetic properties in CrX (XP, As and Sb)

Ito, Tomoaki; Ido, Hideaki; Motizuki, Kazuko

doi:10.1016/j.jmmm.2006.10.470

Cited by 16 publications

(13 citation statements)

References 7 publications

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“…The density of states (DOS) shown in Fig. 2(b), which is almost consistent with a previous report [25]. In this figure, the red, green and blue curves indicate the partial DOS from Cr-d, As-p, and Cr-p orbitals, respectively.…”

Section: Detection Of An Unconventional Superconducting Phase In the ...supporting

confidence: 91%

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs UsingAs75-Nuclear Quadrupole Resonance

et al. 2015

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Pressure-induced superconductivity was recently discovered in the binary helimagnet CrAs. We report the results of measurements of nuclear quadrupole resonance for CrAs under pressure. In the vicinity of the critical pressure Pc between the helimagnetic (HM) and paramagnetic (PM) phases, a phase separation is observed. The large internal field remaining in the phase-separated HM state indicates that the HM phase disappears through a strong first-order transition. This indicates the absence of a quantum critical point in CrAs; however, the nuclear spin-lattice relaxation rate 1/T1 reveals that substantial magnetic fluctuations are present in the PM state. The absence of a coherence effect in 1/T1 in the superconducting state provides evidence that CrAs is the first Cr-based unconventional superconductor. In a conventional Bardeen-Cooper-Schrieffer (BCS) superconductor, electrons form Cooper pairs through negative interactions via an electron-phonon coupling. This gives a sign-uniform s-wave character to the superconducting (SC) gap symmetry. If positive interactions work electron pairs to induce superconductivity, unconventional superconductivity with a sign-changing order parameter is realized beyond the well-established simple s wave. This fascinating form of superconductivity has been discovered in specific materials, such as heavy fermion systems, high-T c cuprates, organic systems, ruthenate, and recent Fe-based superconductors. A common feature of these materials is that superconductivity appears due to the instability of some degree of freedom, which is mainly induced on the verge of a magnetically ordered phase.Very recently, Wu et al. and Kotegawa et al. independently discovered pressure-induced superconductivity in CrAs in the vicinity of the helimagnetic (HM) phase [1,2]. This is the first example of superconductivity found in a Cr-based magnetic system. CrAs has a MnPtype orthorhombic crystal structure with a P nma space group. This structure possesses a space-inversion symmetry, but it is locally missing at the Cr and As sites, and both of these atoms form a zigzag chain along the a-axis. The magnetic transition of the first order into a double-helical state occurs at T N ∼ 265 K. This transition is accompanied by a large magnetostriction, and a lowering of the crystal structure symmetry has not been reported [3,4]. The propagation vector is incommensurate with 0.354 · 2πc * , where c * is a unit vector along the c axis, and magnetic moments of ∼ 1.7µ B /Cr lie in the ab plane [5,6]. The application of pressure drastically suppresses T N , and the HM phase disappears above a critical pressure of P c ∼ 0.7 GPa [1,2,7]. Superconductivity appears together with the suppression of the HM phase, showing a maximum SC transition temperature of T c ∼ 2.2 K at ∼ 1.0 GPa, after which T c decreases gradually with increasing pressure. The pressure-temperature phase diagram of CrAs with a first-order magnetic transition is reminiscent of those of some pressure-induced Fe-based superconductors, such as SrFe 2 As 2 ...

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Section: Detection Of An Unconventional Superconducting Phase In the ...supporting

confidence: 91%

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs UsingAs75-Nuclear Quadrupole Resonance

et al. 2015

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“…Half-metallicity arises as a result of interplay between the exchange splitting and the hybridization. Some Cr-based chalcogenides and pnictides, 17,[24][25][26][27][28][29][30][31][32][33][34] have been predicted to be not only HM but also potential candidates for possessing high Curie temperatures T c . Akinaga et al 24 have reported growing ZB thin films of CrAs on GaAs (001) substrates via molecular beam epitaxy.…”

Section: Half-metallic (Hm) Ferromagnetismmentioning

confidence: 99%

First-principles theoretical studies of half-metallic ferromagnetism in CrTe

2010

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Using full-potential linear augmented plane wave method (FP-LAPW) and the density functional theory, we have carried out a systematic investigation of the electronic, magnetic, and cohesive properties of the chalcogenide CrTe in three competing structures: rock-salt (RS), zinc blende (ZB) and the NiAs-type (NA) hexagonal. Although the ground state is of NA structure, RS and ZB are interesting in that these fcc-based structures, which can possibly be grown on many semiconductor substrates, exhibit half-metallic phases above some critical values of the lattice parameter. We find that the NA structure is not half-metallic at its equilibrium volume, while both ZB and RS structures are. The RS structure is more stable than the ZB, with an energy that is lower by 0.25 eV/atom. While confirming previous results on the half-metallic phase in ZB structure, we provide hitherto unreported results on the half-metallic RS phase, with a gap in the minority channel and a magnetic moment of 4.0 µB per formula unit. A comparison of total energies for the ferromagnetic (FM), nonmagnetic (NM), and antiferromagnetic (AFM) configurations shows the lowest energy configuration to be FM for CrTe in all the three structures. The FP-LAPW calculations are supplemented by linear muffin-tin orbital (LMTO) calculations using both local density approximation (LDA) and LDA+U method. The exchange interactions and the Curie temperatures calculated via the linear response method in ZB and RS CrTe are compared over a wide range of the lattice parameter. The calculated Curie temperatures for the RS phase are consistently higher than those for the ZB phase.

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“…In the literature there are only few theoretical investigations on the electronic structure and magnetic properties of CrTe, CrSe, and CrSb based on first principles electronic structure calculations. Ito et al16 analyzed the electronic structure of CrSb using the full potential linear muffin‐tin orbital (FP‐LMTO) method and compared it with that of CrP and CrAs having the MnP type of structure. For the AFM state they found the Cr magnetic moment to be equal to 2.7 μ B .…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure and Magnetic Properties of Chromium Chalcogenides and Pnictides with NiAs Structure

Polesya¹,

Kuhn²,

Benea

et al. 2013

Zeitschrift anorg allge chemie

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Abstract. The structural as well as electronic and magnetic properties of chromium chalcogenides and pnictides with NiAs structure were studied using the Korringa-Kohn-Rostoker (KKR) band structure method. The magnetic properties at finite temperature were investigated by means of Monte Carlo simulations on the basis of a classical Heisenberg Hamiltonian and the exchange coupling parameters calculated from first principles. Combination of ab initio electronic structure calculations with Monte Carlo simulations allowed to investigate both

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Electronic structure and magnetic properties in CrX (XP, As and Sb)

Cited by 16 publications

References 7 publications

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs UsingAs75-Nuclear Quadrupole Resonance

Detection of an Unconventional Superconducting Phase in the Vicinity of the Strong First-Order Magnetic Transition in CrAs UsingAs75-Nuclear Quadrupole Resonance

First-principles theoretical studies of half-metallic ferromagnetism in CrTe

Electronic Structure and Magnetic Properties of Chromium Chalcogenides and Pnictides with NiAs Structure

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