اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدSpin-driven symmetry breaking in the frustrated fcc magnet MnS2
302
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We report the characterisation of natural samples of the cubic pyrite mineral MnS2 using very high resolution synchrotron X-ray diffraction techniques. At low temperatures we find a new low temperature polymorph, which results from coupling between magnetic and lattice degrees of freedom. Below the magnetic ordering temperature T_N= 48 K, we detect a pseudo-tetragonal distortion with a tiny c/a ratio of 1.0006. The structure can be refined in the space group Pbca. The symmetry lowering reduces magnetic frustration in the fcc Mn2+ lattice and is likely responsible for the previously reported lock-in of the magnetic propagation vector. This behaviour is similar to the frustration driven symmetry breaking reported in other three-dimensional Heisenberg magnets like the chromate spinels
قيم البحث
اقرأ أيضاً
Collective behaviour of electrons, frustration induced quantum fluctuations and entanglement in quantum materials underlie some of the emergent quantum phenomena with exotic quasi-particle excitations that are highly relevant for technological applic
ations. Frustrated quantum materials offer an exciting venue to realize highly entangled quantum states with fractional excitations. Herein, we present our thermodynamic and muon spin relaxation measurements on the recently synthesized frustrated antiferromagnet Li4CuTeO6, in which Cu2+ ions (S = 1/2) constitute a disordered triangular-lattice in the crystallographic ab-plane. Our experiments detect neither long-range magnetic ordering nor spin freezing down to a temperature of 1.55 K despite the presence of strong antiferromagnetic interaction between Cu2+ moments leading to a large Curie-Weiss temperature of -163 K. Muon spin relaxation results demonstrate a dynamic liquid-like quantum state. The temperature and magnetic field scaling of magnetization and specific heat reveal a data collapse pointing towards the presence of random-singlets within a disorder-driven correlated and dynamic ground-state in this frustrated antiferromagnet.
We establish the double perovskite Ba$_2$CeIrO$_6$ as a nearly ideal model system for j=1/2 moments, with resonant inelastic x-ray scattering indicating a deviation of less than 1% from the ideally cubic j=1/2 state. The local j=1/2 moments form an f
cc lattice and are found to order antiferromagnetically at $T_N$=14K, more than an order of magnitude below the Curie-Weiss temperature. Model calculations show that the geometric frustration of the fcc Heisenberg antiferromagnet is further enhanced by a next-nearest neighbor exchange, indicated by ab initio theory. Magnetic order is driven by a bond-directional Kitaev exchange and by local distortions via a strong magneto-elastic effect - both effects are typically not expected for j=1/2 compounds making Ba2CeIrO6 a riveting example for the rich physics of spin-orbit entangled Mott insulators.
We report the direct observation of a magnetic-feld induced long-wavelength spin spiral modulation in the chiral compound Ba3TaFe3Si2O14. This new spin texture emerges out of a chiral helical ground state, and is hallmarked by the onset of a unique c
ontribution to the bulk electric polarization, the sign of which depends on the crystal chirality. The periodicity of the feld induced modulation, several hundreds of nm depending on the field value, is comparable to the length scales of mesoscopic topological defects such as skyrmions, merons and solitons. The phase transition and observed threshold behavior are consistent with a phenomenology based on the allowed Lifshitz invariants for the chiral symmetry of langasite, which intriguingly contain all the ingredients for the possible realization of topologically stable antiferromagnetic skyrmions.
We show that the highly frustrated transverse-field Ising model on the three-dimensional pyrochlore lattice realizes a first-order phase transition without symmetry breaking between the low-field Coulomb quantum spin liquid and the high-field polariz
ed phase. The quantum phase transition is located quantitively by comparing low- and high-field series expansions. Furthermore, the intriguing properties of the elementary excitations in the polarized phase are investigated. We argue that this model can be achieved experimentally by applying mechanical strain to a classical spin ice material comprised of non-Kramers spins such as Ho_2Ti_2O_7. Taken together with our results, this provides a new experimental platform to study quantum spin liquid physics.
Engineering and enhancing inversion symmetry breaking in solids is a major goal in condensed matter physics and materials science, as a route to advancing new physics and applications ranging from improved ferroelectrics for memory devices to materia
ls hosting Majorana zero modes for quantum computing. Here, we uncover a new mechanism for realising a much larger energy scale of inversion symmetry breaking at surfaces and interfaces than is typically achieved. The key ingredient is a pronounced asymmetry of surface hopping energies, i.e. a kinetic energy-driven inversion symmetry breaking, whose energy scale is pinned at a significant fraction of the bandwidth. We show, from spin- and angle-resolved photoemission, how this enables surface states of 3d and 4d-based transition-metal oxides to surprisingly develop some of the largest Rashba-like spin splittings that are known. Our findings open new possibilities to produce spin textured states in oxides which exploit the full potential of the bare atomic spin-orbit coupling, raising exciting prospects for oxide spintronics. More generally, the core structural building blocks which enable this are common to numerous materials, providing the prospect of enhanced inversion symmetry breaking at judiciously-chosen surfaces of a plethora of compounds, and suggesting routes to interfacial control of inversion symmetry breaking in designer heterostructures.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
