Spin- and valley-polarized transport through ferromagnetic and antiferromagnetic barriers on monolayer MoS 2 P.M. Krstajić a,n , P. Vasilopoulos b , M. Tahir b a Institute of Microelectronic Technologies and Single Crystals (IHTM), University of Belgrade, Njegoševa 12, 11000 Belgrade, Serbia b Department of Physics, Concordia University, 7141 Sherbrooke Ouest, Montréal, Québec, Canada H4B 1R6 HIGHLIGHTS  We study electron transport through single/double barriers on monolayer MoS 2 .  The conductance g c and the polarization oscillate with barrier width d.  The conductance versus ferromagnetic field M decreases in a fluctuating manner.  The spin polarization P s oscillates as a function of M before it becomes 100%.  As for AFM barriers the conductance exhibits an oscillating behavior for d 20 nm > . article info Article history: Received 11 August 2015 Received in revised form 25 September 2015 Accepted 1 October 2015 Available online 5 October 2015 Keywords: Quantum transport Low dimensional physics Nanostructures abstract We study ballistic electron transport through single or double barriers on monolayer MoS 2 , of width d, in the presence of a ferromagnetic field M or an antiferromagnetic field F. The total conductance g c , its spin- up and spin-down components, and the polarization oscillate with d or the distance b between two barriers. The corresponding oscillation periods are different. The conductance g c versus M decreases in a fluctuating manner with a steep decline at certain value of M. As a function of M the spin polarization P s oscillates before it becomes 100% while the valley polarization P v oscillates and steadily increases. & 2015 Elsevier B.V. All rights reserved. 1. Introduction Since its discovery graphene has attracted a remarkable at- tention due to its exotic properties and potential applications in various fields [1]. Still there remain fundamental problems due to its zero band gap and weak spin–orbit interaction (SOI). These problems could be overcome by, e.g., using silicene, the silicon analog of graphene, a similar material called germanene, or MoS 2 and other dichalcogenide materials, all of them promising candi- dates for the next generation nanoelectronic devices [2–5]. A re- view of silicene's properties is given in Ref. [6]. Here we focus on MoS 2 , a semiconducting analogue of graphene, which has a hon- eycomb structure similar to graphene's [7]. In addition though, it has a huge intrinsic direct band gap, 1.66 eV wide, and a very large SOI 2 150 meV λ = [7,8]. This strong SOI can lead to spin- and valley-polarized transport and the energy dispersion may be manipulated as recent works indicate [9–11]. Such a transport has been studied in silicene, in which the SOI strength is 3.9 meV, in the presence of exchange fields and led to novel spin and valley polarizations [12,13]. Given the huge gap and very strong SOI in MoS 2 , we expect to find significant differences in similar studies. Here we study spin- and valley-polarized transport through fer- romagnetic (FM) and antiferromagnetic (AFM) barriers in MoS 2 . The paper is organized as follows. In Section 2 we present the basic expressions for ballistic transport through FM barriers as well as the results for the conductance and polarizations. In Sec- tion 3 we do the same for AFM barriers, and in Section 4 we present our conclusions. 2. Ferromagnetic (FM) barriers We consider a monolayer of MoS 2 in the (x,y) plane. Particles in MoS 2 are described by the two-dimensional (2D) Dirac-type Ha- miltonian [14–16] Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/physe Physica E http://dx.doi.org/10.1016/j.physe.2015.10.003 1386-9477/& 2015 Elsevier B.V. All rights reserved. n Corresponding author. E-mail addresses: predrag222@gmail.com (P.M. Krstajić), p.vasilopoulos@concordia.ca (P. Vasilopoulos), m.tahir06@alumni.imperial.ac.uk (M. Tahir). Physica E 75 (2016) 317–321