Implied Employment Contract Terms
The law implies rights and obligations with respect to both parties which will apply unless you and the employee specifically agree otherwise in the employment contract.
Implied terms on the employer include a duty not to destroy the relationship of mutual trust and confidence between employee and employer and to take care of the employee's health and safety.
An employee is under a duty to the employer (during employment) not to use or disclose trade secrets or confidential information, to work with due diligence and care, duties of fidelity and obedience and a duty of good faith, including not competing with you during employment. (These terms may not apply once a garden leave notice is given.)
Both parties are required to give reasonable notice of termination in the absence of an express notice provision in the contract.
You should consider whether such implied terms need either to be excluded or reinforced or extended by specific reference in the employment contract. For example, employee obligations of confidentiality are commonly strengthened and extended in the contract to cover the employee's activities after employment with you has ended.