Valley splitting and polarization by the Zeeman effect in monolayer MoSe2.

We have measured circularly polarized photoluminescence in monolayer MoSe2 under perpendicular magnetic fields up to 10 T. At low doping densities, the neutral and charged excitons shift linearly with field strength at a rate of ∓0.12  meV/T for emission arising, respectively, from the K and K' valleys. The opposite sign for emission from different valleys demonstrates lifting of the valley degeneracy. The magnitude of the Zeeman shift agrees with predicted magnetic moments for carriers in the conduction and valence bands. The relative intensity of neutral and charged exciton emission is modified by the magnetic field, reflecting the creation of field-induced valley polarization. At high doping levels, the Zeeman shift of the charged exciton increases to ∓0.18  meV/T. This enhancement is attributed to many-body effects on the binding energy of the charged excitons.

[1]  G. Wang,et al.  Giant enhancement of the optical second-harmonic emission of WSe(2) monolayers by laser excitation at exciton resonances. , 2015, Physical review letters.

[2]  Aaron M. Jones,et al.  Magnetic control of valley pseudospin in monolayer WSe2 , 2014, Nature Physics.

[3]  Andras Kis,et al.  Valley Zeeman effect in elementary optical excitations of monolayer WSe2 , 2014, Nature Physics.

[4]  Jing Kong,et al.  Valley-selective optical Stark effect in monolayer WS2. , 2014, Nature materials.

[5]  D. Ralph,et al.  Breaking of valley degeneracy by magnetic field in monolayer MoSe2. , 2014, Physical review letters.

[6]  Xiaodong Cui,et al.  Exciton Binding Energy of Monolayer WS2 , 2014, Scientific Reports.

[7]  Lain-Jong Li,et al.  Ultrafast generation of pseudo-magnetic field for valley excitons in WSe2 monolayers , 2014, Science.

[8]  J. Shan,et al.  Tightly bound excitons in monolayer WSe(2). , 2014, Physical review letters.

[9]  Xiaodong Xu,et al.  Dirac cones and Dirac saddle points of bright excitons in monolayer transition metal dichalcogenides , 2014, Nature Communications.

[10]  Wang Yao,et al.  Spin and pseudospins in layered transition metal dichalcogenides , 2014, Nature Physics.

[11]  H. Y. Chen,et al.  Magnetoelectronic and optical properties of a MoS2 monolayer , 2014 .

[12]  S. Louie,et al.  Giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor. , 2014, Nature materials.

[13]  S. Louie,et al.  Probing excitonic dark states in single-layer tungsten disulphide , 2014, Nature.

[14]  P. L. McEuen,et al.  The valley Hall effect in MoS2 transistors , 2014, Science.

[15]  Timothy C. Berkelbach,et al.  Exciton binding energy and nonhydrogenic Rydberg series in monolayer WS(2). , 2014, Physical review letters.

[16]  E. Malic,et al.  Analytical approach to excitonic properties of MoS2 , 2013, 1311.1045.

[17]  S. Louie,et al.  Optical spectrum of MoS2: many-body effects and diversity of exciton states. , 2013, Physical review letters.

[18]  K. Ko'smider,et al.  Large spin splitting in the conduction band of transition metal dichalcogenide monolayers , 2013, 1311.0049.

[19]  Shengyuan A. Yang,et al.  Magnetic control of the valley degree of freedom of massive Dirac fermions with application to transition metal dichalcogenides , 2013, 1309.3814.

[20]  Yugui Yao,et al.  Three-band tight-binding model for monolayers of group-VIB transition metal dichalcogenides , 2013, 1305.6089.

[21]  Timothy C. Berkelbach,et al.  Theory of neutral and charged excitons in monolayer transition metal dichalcogenides , 2013, 1305.4972.

[22]  Yong-Wei Zhang,et al.  Quasiparticle band structures and optical properties of strained monolayer MoS 2 and WS 2 , 2012, 1211.5653.

[23]  Aaron M. Jones,et al.  Electrical control of neutral and charged excitons in a monolayer semiconductor , 2012, Nature Communications.

[24]  J. Shan,et al.  Tightly bound trions in monolayer MoS2. , 2012, Nature materials.

[25]  A. Krasheninnikov,et al.  Effects of confinement and environment on the electronic structure and exciton binding energy of MoS2 from first principles , 2012 .

[26]  B. Jonker,et al.  Valley polarization and intervalley scattering in monolayer MoS$_{2}$ , 2012 .

[27]  A. Ramasubramaniam.  Large excitonic effects in monolayers of molybdenum and tungsten dichalcogenides , 2012 .

[28]  P. Tan,et al.  Robust optical emission polarization in MoS2 monolayers through selective valley excitation , 2012, 1206.5128.

[29]  Ji Feng,et al.  Valley-selective circular dichroism of monolayer molybdenum disulphide , 2012, Nature Communications.

[30]  Keliang He,et al.  Control of valley polarization in monolayer MoS2 by optical helicity. , 2012, Nature nanotechnology.

[31]  Walter R. L. Lambrecht,et al.  Quasiparticle band structure calculation of monolayer, bilayer, and bulk MoS 2 , 2012 .

[32]  Wang Yao,et al.  Valley polarization in MoS2 monolayers by optical pumping. , 2012, Nature nanotechnology.

[33]  Wang Yao,et al.  Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. , 2011, Physical review letters.

[34]  J. Shan,et al.  Atomically thin MoS₂: a new direct-gap semiconductor. , 2010, Physical review letters.

[35]  A. Splendiani,et al.  Emerging photoluminescence in monolayer MoS2. , 2010, Nano letters.

[36]  Wang Yao,et al.  Valley-dependent optoelectronics from inversion symmetry breaking , 2007, 0705.4683.

[37]  Wang Yao,et al.  Valley-contrasting physics in graphene: magnetic moment and topological transport. , 2007, Physical review letters.

[38]  M. Shayegan,et al.  Valley splitting of AlAs two-dimensional electrons in a perpendicular magnetic field. , 2002, Physical review letters.

[39]  Cox,et al.  Bound states in optical absorption of semiconductor quantum wells containing a two-dimensional electron Gas , 2000, Physical review letters.

[40]  T. Reinecke,et al.  Exciton diamagnetic shift in semiconductor nanostructures , 1998 .

[41]  A. Forchel,et al.  Exciton binding energies and diamagnetic shifts in semiconductor quantum wires and quantum dots , 1998 .

[42]  Physical Review Letters 63 , 1989 .