Two-dimensional layered materials, such as transition metal dichalcogenides (TMDCs), are promising materials for future electronics owing to their unique electronic properties. With the presence of a band gap, atomically thin gate defined quantum dots (QDs) can be achieved on TMDCs. Herein, standard semiconductor fabrication techniques are used to demonstrate quantum confined structures on WSe2 with tunnel barriers defined by electric fields, therefore eliminating the edge states induced by etching steps, which commonly appear in gapless graphene QDs. Over 40 consecutive Coulomb diamonds with a charging energy of approximately 2 meV were observed, showing the formation of a QD, which is consistent with the simulations. The size of the QD could be tuned over a factor of 2 by changing the voltages applied to the top gates. These results shed light on a way to obtain smaller quantum dots on TMDCs with the same top gate geometry compared to traditional GaAs/AlGaAs heterostructures with further research.

Exchange coupling constants (J) are fundamental to the understanding of spin spectra of magnetic systems. Here we investigate the broken-symmetry (BS) approaches of Noodleman and Yamaguchi in conjunction with coupled cluster (CC) methods to obtain exchange couplings. J values calculated from CC in this fashion converge smoothly towards the FCI result with increasing level of CC excitation. We compare this BS-CC scheme to the complementary EOM-CC approach on a selection of bridged molecular cases and give results from a few other methodologies for context.

Reactions involving reductive aggregation of MnO 4− in methanol in the presence of Ce IV and an excess of carboxylic acid have led to the synthesis of structurally related Ce/ Mn clusters, [Ce 3 Mn 5 O 8 (OMe)(O 2 CBu t ) 13 (MeOH)] (1) and [Ce 2 Mn 3 O 5 (O 2 CPh) 9 (MeOH) 3 ] (2), containing at least one {Mn 2 Ce 2 O 4 } cubane unit. The cores of both clusters contain Mn x units separated by three (1) or two (2) Ce IV ions. Fits of variable-temperature, solid-state dc and ac magnetic susceptibility data reveal dominant ferromagnetic interactions within 1 and 2, resulting in the maximum S = 17 / 2 and S = 5 ground state spins, respectively, and thus suggesting significant ferromagnetic (F) interactions between the Mn x units that are ≥6 Å apart and separated by four intervening bonds through diamagnetic Ce IV . Fits of magnetic susceptibility data also revealed unusual long-range F interactions, and this finding was further supported by high-field EPR measurements and simulations. Density functional theory calculations and a Wannier function analysis confirm long-range interactions and indicate a Mn−Ce−Mn superexchange pathway via Mn-d/Ce-f orbital overlap/hybridization

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