What caused the rift that developed between Jefferson and Washington?

This actually needs a detailed answer. 

In 1795, Washington and Chief Justice John Jay brokered a treaty with England that favored English imports and guaranteed payment on pre-revolutionary debts. Though it did compromise American strength, Washington's primary purpose was to avoid a war the country could not afford, and he hoped England would triumph over France. He hoped that favoring that nation would buy America the protection of the British fleet; this proved prophetic, as it happened well into the 19th century in some form or another. However, many of Washington's contemporaries lacked his foresight, and considered Jay's Treaty an act of treason against the principles of the Revolution. It was not only that America compromised its identity - it was that the country did so with its former enemy. Mobs cursed Washington, and demanded war with England. Although the Constitution granted the power to negotiate treaties solely to the executive branch, the House of Representatives was able to veto them. Madison and Jefferson endeavored to negate Jay's Treaty, but Washington's popularity proved superior, and they were unable to find the votes.

Unsurprisingly, Jefferson was outraged. His beliefs - that individuals should counter any form of centralized authority - had only strengthened in the face of Hamilton's financial plan and Jay's Treaty. It was exacerbated by his notorious pro-French sentiment. Jefferson even payed credence to conspiracy theories claiming that closeted Tories were reclaiming the country for England from behind closed doors. Jefferson believed fully in a Federalist conspiracy to overthrow the government. Further, he believed Washington was unaware of, or unable to counter, this conspiracy.

Jefferson’s opinion of the President had greatly shifted during the Whiskey Rebellion (1791-1794), when a small group of farmers from Pennsylvania protested taxes levied on alcohol. Viewing their rebellion as a direct threat to the authority of the federal government, Washington sent in the militia to quash them. Jefferson wanted to blame Hamilton and the Federalists for this use of power, but ultimately concluded that Washington had grown senile and totalitarian. He spread these rumors throughout the Republican party and the press, and though he always denied being the instigator, Washington knew well that Jefferson was the guilty party. All correspondence between Mount Vernon and Monticello ceased.

This rift with Jefferson illustrates the fundamental division within Washington’s Presidency: the Republicans vs. the Federalists. Rules of political conduct were not yet established (if they ever have been), and Jefferson continued to control the Republican opposition from his perch in Monticello, rather than from the capitol. His delusions concerning the Federalists were so well known throughout Virginia’s political elite, that his protégé James Monroe sewed dissent through his position as the Minister to France. While there, Monroe assured the French that Jay’s Treaty would not be approved by Congress, and that the majority of Americans wanted to join France in their war against England. Monroe even proposed a $5 million loan, and said that any messages from Washington should be disregarded, since he would soon be thrown from office by pro-French supporters in America. Monroe also leaked confidential information to the press, a traitorous offence for anyone, but especially for a man who would one day become President of the United States.