Superconductivity series in transition metal dichalcogenides by ionic gating article pdf available in scientific reports 5. Monolayer transition metal dichalcogenide tmd superconductors in particular lack inversion symmetry, yielding an antisymmetric form of spinorbit. Metal atoms are distorted further or dimerized in one direction, called t. Firstprinciples study of charge density waves, electron. Twodimensional atomic layers of transition metal dichalcogenides tmds such as molybdenum disulfide mos 2 and tungsten diselenide wse 2 exhibit extraordinary optoelectronic properties.
Unconventional scaling of the superfluid density with the. Superconductivity series in transition metal dichalcogenides by ionic gating. Band structures of transition metal dichalcogenides. Synthetic metals, 5 1983 229 244 229 effect of alloying and intercalation on super conductivity of transition metal dichalcogenides m. Here, we use a combined numerical and grouptheoretical approach in realspace to characterize the unconventional superconducting state in monolayer transition metal dichalcogenides. Starting with the isolation of a single sheet of graphene, the study of layered materials has been one of the most active areas of condensed matter physics, chemistry, and materials science.
Here, we demonstrate that, by only manual shaking within several seconds, very largesized tmd monolayers that cover a wide range of group ivbvib transition metal sulfides and. Systems simultaneously exhibiting superconductivity and spinorbit coupling are predicted to provide a route toward topological superconductivity and unconventional electron pairing, driving significant contemporary interest in these materials. Muto the research institute for iron, steel and other metals, tohoku university, sendai 980 japan summary the superconducting transition temperature te and the anisotropy ratio of the upper critical field parallel. Optical and excitonic properties of atomically thin. Law department of physics, hong kong university of science and technology, clear water bay, hong kong, china in monolayer transition metal dichalcogenides tmds, electrons in opposite kvalleys are subject. Number of researchers have fascinated by the motivating properties of the compounds of this family. Pdf superconductivity in transition metal dichalcogenides. In tmds, one unit layer is 3atoms thick in which the transition metal m atom is sandwiched between two chacogens x, giving the stoichiometry mx 2 1. Furthermore, numerous studies focus on 2d materials that are analogous to graphene as electrode supercapacitors, including transition metal dichalcogenides tmds. Crystallographic data for the group vi a dichalcogenides mos, mose, mote, ws, wse, a 4 3. Figure 1a illustrates the crystal structure of 2htype transition metal dichalcogenides, mx 2 m mo or w. There is a general tendency for group 47 metal dichalcogenides to form layered structures, in contrast to group 810 metals, like pyrites, which prefer nonlayered structures.
We explored how to improve the thermoelectric properties of the layered transitionmetal dichalcogenides 2hmq2 m mo, w. Ge, yizhi georgetown university, 20 in this thesis we investigate the electronic and vibrational properties of several transition metal dichalcogenide materials through firstprinciples calculations. Recent advances in atomically thin twodimensional transition metal dichalcogenides 2d tmds have led to a variety of promising technologies for nanoelectronics, photonics, sensing, energy storage, and optoelectronics, to name a few. Effect of alloying and intercalation on superconductivity. A monolayer of tmd is formed by a layer of transition metal atoms with a triangular lattice sandwiched by two identical layers of chalcogen atoms with a triangular lattice as shown in fig. Nbsete a new layered transition metal dichalcogenide superconductor.
Pdf straindependent modulation of conductivity in single. Github evansosenkoapsdichalcogenidessuperconductivity. Spinorbit coupling in transition metal dichalcogenides tmdcs causes spin valley locking, giving rise to unconventional optical, transport, and. Modulating optoelectronic properties of twodimensional. The ideality factor of the npn structure was estimated to be. Straindependent modulation of conductivity in single layer transition metal dichalcogenides m. Nodal liquid and swave superconductivity in transition. Engineering electronic properties of layered transitionmetal. Amonolayer transition metal dichalcogenide tmd is formed by a. Heine school of engineering and science, jacobs university bremen, campus ring 1, 28759 bremen, germany october 30, 2018 abstract quantum conductance calculations on the mechanically deformed monolayers of. Transition metal dichalcogenide monolayers wikipedia. Transition metal dichalcogenides tmdcs have been widely. Monolayer transition metal dichalcogenide tmd is promising to host features of topological superconductivity. Owing to strong spin orbit coupling, 2d 2hnbse2 demonstrates unconventional superconductivity that allows both spinsinglet and spintriplet cooper pairing.
Specifically, we identify monolayer holedoped transition metal dichalcogenide tmds as candidates for topological superconductors out of such momentum. Intercalation of the layer type transition metal dichalcogenides by a variety of organic molecules, alkali metals, or 3d transition metals, provides a powerful way to finely tune the electron occupation of the relatively narrow d bands met in these solids. Superconductivity in 2d transition metal dichalcogenide x. Topological superconductivity in monolayer transition metal dichalcogenides yiting hsu1, abolhassan vaezi2, mark h. Pdf transport evidence of ising superconductivity in fewlayer 1td. In the macroscopic bulk crystal, or more precisely, for an even number of monolayers, the. Of the sixty compounds of this family, about twothirds assume layer structures. The lowest work function of materials reported so far is in a range of about 1 ev. Effect of alloying and intercalation on superconductivity of.
Tmds are materials of the form mx 2, where m represents a transition metal atom such as mo, w, ta etc. Functionalities of twodimensional 2d crystals based on semiconducting transition metal dichalcogenides tmds have now stemmed from simple field effect transistors fets to a variety of. Ising superconductivity and majorana fermions in transition metal dichalcogenides tong zhou, hongliang jiang, noah f. Phase engineering of twodimensional transition metal. A monolayer of tmd is formed by a layer of transition metal atoms with triangular lattice sandwiched by two identical layers of chalcogen atoms with triangular lattice as shown. Band alignment of twodimensional transition metal dichalcogenides. Transition metal dichalcogenides tmds are composed of three atomic planes and often two atomic species. Among these 2d materials, transition metal dichalcogenides. The superconducting transition temperature t c and the anisotropy ratio of the upper critical field parallel and perpendicular to the layer plane have been measured on 2h and 4hanb 1. Superconductivity series in transition metal dichalcogenides.
By mechanical cleavage, atomically flat and chemically stable thin flakes of tmds can be readily obtained from bulk crystals. Muto the research institute for iron, steel and other metals, tohoku university, sendai 980 japan summary the superconducting transition temperature te and the anisotropy ratio of the upper critical field parallel and perpendicular to the. The amazing world of layered transition metal dichalcogenides tmds humberto terrones. Transition metal dichalcogenides are considered as one of the 2d graphene analogues 1. Magnetic field driven nodal topological superconductivity in. We explore the physical properties of a unified microscopic theory for the coexistence of superconductivity and charge density waves in twodimensional transition metal dichalcogenides. Apr 19, 2016 one of the most widely researched classes of these materials is the layered transition metal dichalcogenides tmds. We show how the strong ising spinorbit coupling soc, a special type of. Recently, scientists and researchers are exploring tmds because of the distinct features that make 2d tmds. Recent development of twodimensional transition metal. Application in tunnel field effect transistors cheng gong,1 hengji zhang,2 weihua wang,1 luigi colombo,3 robert m.
That the fieldinduced phase appears with an enhanced t c at a much lower n 2d with respect to the alkali metaldoped compounds confirms the effectiveness of searching for different regions of carrier concentrations in doped semiconductors. Transition metal dichalcogenides characteristically contain layered crystal structures. These features provide exciting opportunities for the. Abstract in this thesis we investigate the electronic and vibrational properties of several transitionmetal dichalcogenide materials through. In this the coordination is octahedral but the unit is distorted from the ideal situation by a tendency. The mechanical exfoliation technique of microsize tmd flakes has attracted particular interest due to its simplicity and cost effectiveness.
Optoelectronics of multijunction heterostructures of. Nbsetea new layered transition metal dichalcogenide. Tmdc family due to its high superconducting transition temperature tc 7. Synthesis, properties and potential applications of two. Tmdcs are 2d nanomaterials consist of a monolayer of transition metal atoms sandwiched xmx between two layers of chalcogen atoms usually selenium, sulfur, or telluride in a hexagonal lattice 2. Superconductivity in potassiumdoped metallic polymorphs. The controllable modulation of optical and electrical properties of tmdcs is of fundamental importance to enable a wide range of future optoelectronic devices. As a potential alternative, gapped semiconducting transition metal dichalcogenides tmds have been introduced into 2d materials research in recent years. Pdf topological superconductivity at the edge of transition. Singlelayer 2d tmds can in turn form two polymorphs, having either. Ising superconductivity and quantum phase transition in. Transition metal dichalcogenides every individual layer of bulk tmds mx 2 is composed of a transition metal m atomic layer between two chalcogen x atomic layers figure 1a.
Super low work function of alkalimetaladsorbed transition. Transition metal dichalcogenides tmdcs usually exhibit layered polytypic structures due to the weak interlayer coupling. We show how the strong ising spinorbit coupling soc, a special type of soc which pins electron spins to outofplane directions, can affect the superconducting. Twodimensional 2d transition metal dichalcogenides tmds have a range of unique physics properties and could be used in the development of electronics, photonics, spintronics, and quantum computing devices. In particular, 2d transition metal dichalcogenides 2d. Pdf ising superconductivity and majorana fermions in transition. In the mos 2 motif, which is not observed for dihalides, the metals exhibit trigonal prismatic structures. For the last few decade scientists are beginning to turn to transition metal dichalcogenides shortly known as tmdcs.
Superconductivity in large spinorbit coupled material. Synthesis and physical properties of phaseengineered. In contrast to the graphene sheet, they are chemically versatile. With the nearly full occupation of the d orbitals, 2d ntmds are expected to be more attractive due to the unique interlayer vibrational behaviors and largely tunable electronic structures. Ge, yizhi georgetown university, 20 in this thesis we investigate the electronic and vibrational properties of several transitionmetal dichalcogenide materials through firstprinciples calculations. In the macroscopic bulk crystal, or more precisely, for an even number of monolayers, the crystal structure has an inversion center. In the cdi 2 motif, the metals exhibit octahedral structures. Superconductivity in 2d transition metal dichalcogenide xfeng.
More recently, another twodimensional material, monolayers of transition metal dichalcogenides tmds such as mos2, wse2, nbse2, have been successfully isolated 3, 4. Molybdenum disulfide mos2 is the most studied representative of this family of materials, especially. Ising superconductivity in transition metal dichalcogenides noah f. Condensed matter physics copyright 2019 unconventional. Phase engineering of transition metal dichalcogenides. Pdf hosted at the radboud repository of the radboud university. Superconducting layered transition metal dichalcogenides tmds stand out among other superconductors due to the tunable nature of the superconducting transition, coexistence with other collective electronic excitations charge density waves, and strong intrinsic spinorbit coupling. Junh ua zhang, and vivek aji department of physics, university of california, riverside, r iverside, california. Transport studies in 2d transition metal dichalcogenides and. The coexistence of cdw with superconductivity poses an. Topological superconductivity in monolayer transition. Many transition metal dichalcogenides tmds have layered structure similar to graphite.
Atomically thin transition metal dichalcogenides tmdcs have attracted great interest as a new class of twodimensional 2d direct band gap semiconducting materials. Spontaneous selfintercalation of copper atoms into. Probing ising superconductivity and lightinduced phase. Topological superconductivity in monolayer transition metal. Applications for these materials include high speed electronics, flexible devices, next generation solar cells, and touch screen display panels. Jul 17, 2017 transition metal dichalcogenide tmd materials have recently demonstrated exceptional supercapacitor properties after conversion to a metallic phase, which increases the conductivity of the network. Semiconducting transition metal dichalcogenides tmds have attracted considerable interest as typical twodimensional 2d materials. Ising superconductivity in transition metal dichalcogenides arxiv. Functionalities of twodimensional 2d crystals based on semiconducting transition metal dichalcogenides tmds have now stemmed from simple field effect transistors fets to a variety of electronic and optovalleytronic devices, and even to superconductivity.
Berry curvature dipole current in the transition metal. Tmds with mx 2 stoichiometry, where m is a transition metal and x is a chalcogen, have attracted much attention due to their potential applications in the fields of spintronics, 1 valleytronics, 2, 3 optoelectronics, 4 and field. Phase engineering of twodimensional transition metal dichalcogenides yao xiao1, mengyue zhou2, jinglu liu2, jing xu2 and lei fu1,2 abstract twodimensional 2d transition metal dichalcogenides tmds have gained much attention in virtue of their various atomic configurations and band structures. Transition metal dichalcogenides tmdcs, which are semiconductors of the type mx 2, where m is a transition metal atom such as mo or w and x is. Unconventional superconductivity and anomalous response in holedoped transition metal dichalcogenides. Wallace,1,2 and kyeongjae cho1,2,a 1department of materials science and engineering, the university of texas at dallas, richardson, texas 75080, usa.
Atomicscale engineering of chemicalvapordepositiongrown 2d transition metal dichalcogenides for electrocatalysis. Department of physics, applied physics and astronomy. Unsaturated single atoms on monolayer transition metal. Singlelayer transition metal dichalcogenides are directgap semiconducting analogs of graphene that exhibit novel electronic and optical properties.
In the case of particlehole symmetry the elementary particles are dirac fermions at the nodes of the charge density wave gap. Enhancing the thermoelectric properties of layered transition. Here, this study demonstrates that a consecutive structural phase transition from t d to 1t. Straindependent modulation of conductivity in single layer. Oddparity superconductivity in bilayer transition metal.
Graphene and monolayer transitionmetal dichalcogenides. Graphene is very popular because of its many fascinating properties, but its lack of an electronic bandgap has stimulated the search for 2d materials with semiconducting character. Rapid synthesis of transition metal dichalcogenidecarbon. Transition metal dichalcogenides tmds are a class of layered materials, which presently attract great interest because of their versatile physical, chemical, and mechanical properties 111. Transition metal dichalcogenides tmdcs 14have lately attracted considerable attention because of their rich physics, such as charge density waves 57, a super conducting phase 8, twodimensional 2d quantum spin hall qsh states 9, and weyl semimetal states 14, among other phenomena. The strong bonding between the metal and chalcogenide ligands, contrasts with the weak chalcogenidechalcogenide. Superconductivity in transition metal dichalcogenides evan sosenko. The chemistry of twodimensional layered transition metal. Transition metal dichalcogenides typically adopt either cadmium diiodide or molybdenum disulfide structures. Electronic properties of intercalation complexes of the. Reports superconducting dome in a gatetuned band insulator.
Intercalated transition metal dichalcogenides tmds have attracted substantial interest due to their exciting electronic properties. Dimensional transition metal carbides and nitrides. Recently, coupling with high efficient ionic media, tmd thin flakes have exhibited extraordinary electronic and opto. Aug 03, 2015 functionalities of twodimensional 2d crystals based on semiconducting transition metal dichalcogenides tmds have now stemmed from simple field effect transistors fets to a variety of electronic and optovalleytronic devices, and even to superconductivity. For twodimensional transition metal dichalcogenides tmd materials, achieving large size with high quality to provide a basis for the next generation of electronic device geometries has been a longterm need. Tuning ising superconductivity with layer and spinorbit. Here, to design low work function materials, we perform firstprinciples calculations on selected materials of transition metal dichalcogenide as substrates and alkali metals as adsorbates. Firstprinciples study of charge density waves, electronphonon coupling, and superconductivity in transitionmetal dichalcogenides. Chapter 1 existing information about transition metal. Abstract with broken space symmetry and strong quantum fluctuation, 2 dimensional materials in different systems always show distinguished properties from the bulk. Selected area diffraction patterns for 1 ttas2 with incident electron beam parallel to c a the 1 t phase at 340 k showing strong triangular groupings sm 10. Among pn junction devices with multilayered heterostructures with wse2 and mose2, a device with the mose2wse2mose2 npn structure showed a remarkably high photoresponse, which was times higher than the mose2wse2 np structure. Since the early 60s a group of materials called the transition metal dichalcogenides have received a rapidly growing interest. Superconductivity series of iongated transition metal.
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