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abstract: REVIEW Semiconductor devices generally take advantage of the charge of electrons, whereas magnetic materials are used for recording information involving electron spin. To make use of both charge and spin of electrons in semiconductors, a high concentration of magnetic elements can be introduced in nonmagnetic III V semiconductors currently in use for devices. Low solubility of magnetic elements was overcome by low temperature nonequilibrium molecular beam epitaxial growth, and ferromagnetic (Ga,Mn)As was realized. Magnetotransport measurements revealed that the magnetic transition temperature can be as high as 110 kelvin. The origin of the ferromagnetic interaction is discussed. Multilayer heterostructures including resonant tunneling diodes (RTDs) have also successfully been fabricated. The magnetic coupling between two ferromagnetic (Ga,Mn)As films separated by a nonmagnetic layer indicated the critical role of the holes in the magnetic coupling. The magnetic coupling in all semiconductor ferromagnetic/nonmagnetic layered structures, together with the possibility of spin filtering in RTDs, shows the potential of the present material system for exploring new physics and for developing new functionality toward future electronics.
title: Making nonmagnetic semiconductors ferromagnetic
venue: Science
year: 1998

abstract: clicking here colleagues, clients, or customers by you can order high quality copies for your If you wish to distribute this article to others here following the guidelines can be obtained by Permission to republish or repurpose articles or portions of articles (this information is current as of May 6, 2010 The following resources related to this article are available online at www.sciencemag.org http:/www.sciencemag.org/cgi/content/full/281/5379/951 version of this article at: including high resolution figures, can be found in the online Updated information and services, http:/www.sciencemag.org/cgi/content/full/281/5379/951#otherarticles 2 of which can be accessed for free: cites 25 articles This article 2070 article(s) on the ISI Web of Science. cited by This article has been http:/www.sciencemag.org/cgi/content/full/281/5379/951#otherarticles 9 articles hosted by HighWire Press; see: cited by This article has been http:/www.sciencemag.org/cgi/collection/mat_sci Materials Science subject collections This article appears in the following
author_names: Hideo Ohno
title: Making Nonmagnetic Semiconductors Ferromagnetic H
year: 2010

abstract: Proximity effects in two dimensional (2D) van der Waals heterostructures offer controllable ways to tailor the electronic band structure of adjacent materials. Exchange proximity in particular is important for making materials magnetic without hosting magnetic ions. Such synthetic magnets could be used for studying magnetotransport in high mobility 2D materials, or magneto optics in highly absorptive nominally nonmagnetic semiconductors. Using first principles calculations, we show that the proximity exchange in monolayer MoSe$_2$ and WSe$_2$ due to ferromagnetic monolayer CrI$_3$ can be tuned (even qualitatively) by twisting and gating. Remarkably, the proximity exchange remains the same when using antiferromagnetic CrI$_3$ bilayer, paving the way for optical and electrical detection of layered antiferromagnets. Interestingly, the proximity exchange is opposite to the exchange of the adjacent antiferromagnetic layer. Finally, we show that the exchange proximity is confined to the layer adjacent to CrI$_3$ and that adding a separating hBN barrier drastically reduces the proximity effect. We complement our it ab initio results with tight binding modeling and solve the Bethe Salpeter equation to provide experimentally verifiable optical signatures (in the exciton spectra) of the proximity exchange effects.
author_names: Klaus Zollner

Paulo E Faria Junior

Jaroslav Fabian
title: Proximity exchange effects in MoSe2 and WSe2 heterostructures with CrI3 Twist angle, layer, and gate dependence
venue: Physical Review B
year: 2019

abstract: We study the photoinduced ferromagnetism in the dilute magnetic semiconductors by solving a Hamiltonian model that consists of localized magnetic moments interacting with the photoexcited itinerant carriers. The spin states of the itinerant carriers are split due to the interaction with the localized magnetic moments, which are assumed to be in thermal equilibrium in the local magnetic field due to the carriers. The time dependence of the light matter interaction term is eliminated by a unitary transformation and the resulting Hamiltonian is solved by making a Bogoliubov Valatin transformation or by a variational approach using a Bardeen Cooper Schrieffer type wave function. Without incident light, there are no carriers present to mediate magnetic interaction between the localized spins, so that the system is nonmagnetic. When light is present, the photoexcited carriers mediate a ferromagnetic interaction between the localized moments resulting in a ferromagnetic state, with a transition to a paramagnetic state as temperature is increased beyond {T}_{c} The magnitude of {T}_{c} is determined by the parameters of the system such as the strength of the light matter coupling, the frequency of light, interaction strength of the carriers with the localized moments, etc. Even for a sub band gap light frequency, there are induced carriers, primarily due to the Rabi oscillations, leading to a small but nonzero {T}_{c} We find that for typical parameters, {T}_{c} is about a fraction of a Kelvin or so, which is sizable. In systems which are already ferromagnetic such as GaAs(Mn) the incident light would enhance the {T}_{c} by this amount, an effect which has been recently observed.
author_names: Subodha Kumar Mishra

Gouri S Tripathi

Sashi Satpathy
title: Theory of photoinduced ferromagnetism in dilute magnetic semiconductors
year: 2008

abstract: Abstract We present two approaches to integrate magnetic materials with III V semiconductors. One is epitaxial ferromagnetic metallic films and heterostructures on GaAs (0 0 1) substrates. Although crystal structure, lattice constant, chemical bonding and other properties are dissimilar, ferromagnetic hexagonal MnAs thin films and MnAs/NiAs ferromagnet/nonmagnet heterostructures (HSs) are grown on GaAs by molecular beam epitaxy (MBE) Multi stepped magnetic hysteresis are controllably realized in MnAs/NiAs HSs, making this material promising for the application to multi level nonvolatile recording on semiconductors. The other approach is to prepare a new class of GaAs based magnetic semiconductor, GaMnAs, by low temperature molecular beam epitaxy (LT MBE) on GaAs (0 0 1) New III V based superlattices consisting of ferromagnetic semiconductor GaMnAs and nonmagnetic semiconductor AlAs are also successfully grown. Structural and magnetic properties of these new heterostructures are presented.
author_names: Masaaki Tanaka
title: Epitaxial ferromagnetic thin films and heterostructures of Mn based metallic and semiconducting compounds on GaAs
year: 1997

abstract: The electronic and magnetic properties of ZrS2 nanoribbons (NRs) are investigated based on first principles calculations. It is found that the ZrS2 NRs with armchair edges are all indirect band gap semiconductors without magnetism, and the band gap exhibits odd even oscillation behavior with the increase of the ribbon width. For the NRs with zigzag edges, those with both edges S terminated are nonmagnetic direct band gap semiconductors, and the gap decreases monotonically as a function of the ribbon width. However, the NRs with one edge S terminated and the other edge Zr terminated are ferromagnetic half metals, while those with both edges Zr terminated tend to be ferromagnetic half metals when the width N 9. The magnetism of both systems mainly originates from the unsaturated edge Zr atoms. Depending on the different edge configurations and ribbon widths, the ZrS2 NRs exhibit versatile electronic and magnetic properties, making them promising candidates for applications in electronics and spintronics.
author_names: Hui Lv

Wensheng Lu

Junguo Li

R C Xiao

Mengying Wei

P Tong

Xiaolian Zhu

Ya-bing Sun
title: Edge controlled half metallic ferromagnetism and direct gap semiconductivity in ZrS2 nanoribbons
year: 2017

abstract: The electronic and magnetic properties of ZrS2 nanoribbons (NRs) are investigated based on the first principles calculations. It is found that the ZrS2 NRs with armchair edges are all indirect band gap semiconductors without magnetism and the band gap exhibits odd even oscillation behavior with the increase of the ribbon width. For the NRs with zigzag edges, those with both edges S terminated are nonmagnetic direct band gap semiconductors and the gap decreases monotonically as a function of the ribbon width. However, the NRs with one edge S terminated and the other edge Zr terminated are ferromagnetic half metal, while those with both edges Zr terminated tend to be ferromagnetic half metal when the width $N\geq9$ The magnetism of both systems mainly originates from the unsaturated edge Zr atoms. Depending on the different edge configurations and ribbon widths, the ZrS2 NRs exhibit versatile electronic and magnetic properties, making them promising candidates for the applications of electronics and spintronics.
author_names: Hongying Lv

W -J Lu

J Y Li

R C Xiao

Mengying Wei

P Tong

X B Zhu

Ya Ping Sun
title: Edge controlled half metallic ferromagnetism and direct gap in ZrS2 nanoribbons
year: 2017

abstract: Abstract We have created a new class of epitaxial magnetic multilayers, consisting of ferromagnetic MnAs and nonmagnetic NiAs, on (001)GaAs substrates by molecular beam epitaxy. It was found that the growth plane of MnAs and NiAs is the 1 100) of hexagonal crystal structure, and that the easy axis of magnetization of MnAs is in plane, along the 1 1 20] axis, which is parallel to the [110] of GaAs. Multi stepped magnetic hysteresis are controllably realized, making this material promising for the application to multi level non volatile recording on semiconductors.
author_names: Masaaki Tanaka

James P Harbison

G M Rothberg
title: MnAs/NiAs magnetic multilayers on GaAs grown by molecular beam epitaxy
year: 1996

abstract: Abstract In this work, we analyze the nonmagnetic random disorder leading to a formation of ferromagnetic clusters in diluted magnetic semiconductors. The nonmagnetic random disorder arises from randomness in the host lattice. Including the disorder to the Kondo lattice model with random distribution of magnetic dopants, the ferromagnetic paramagnetic transition in the system is investigated in the framework of dynamical mean field theory. At a certain low temperature one finds a fraction of ferromagnetic sites transiting to the paramagnetic state. Enlarging the nonmagnetic random disorder strength, the paramagnetic regimes expand resulting in the formation of the ferromagnetic clusters.
author_names: Dinh-Hoi Bui

Van-Nham Phan
title: Ferromagnetic clusters induced by a nonmagnetic random disorder in diluted magnetic semiconductors
year: 2016

author_names: Srijan Kumar Saha

Piotr Ku 'swik

Pedro Lana Gastelois

Marek Przybylski

Valeri S Stepanyuk

J urgen Kirschner
title: Making Nonmagnetic Palladium Ferromagnetic by Antiferromagnetic CoO
year: 2014